Bitcoin Wiki - User contributions [en]

Proof of Stake

2014-04-01T19:18:48Z

Sahtor: /* Cunicula's Note */ Coblee typo, Link to original proposal

Proof of Stake is a proposed alternative to [[Proof of Work]]. Like proof of work, proof of stake provides a mechanism for determining who signs bitcoin transactions (see [https://bitcointalk.org/index.php?topic=68213.0 "main" bitcointalk thread], and a [https://bitcointalk.org/index.php?topic=96854.0 Bounty Thread]).

It was probably first proposed [https://bitcointalk.org/index.php?topic=27787.0 here] by Quantum Mechanic. With Proof of Work, the probability of mining a block depends on the work done by the miner (e.g. CPU/GPU cycles spent checking hashes). With Proof of Stake, the resource that's compared is the amount of Bitcoin a miner holds - someone holding 1% of the Bitcoin can mine 1% of the "Proof of Stake blocks".

Some argue that methods based on Proof of Work alone might lead to a low network security in a cryptocurrency with block incentives that decline over time (like bitcoin) due to [[Tragedy of the Commons]], and Proof of Stake is one way of changing the miner's incentives in favor of higher network security.

= Motivation For Proof of Stake =

* A proof-of-stake system might provide increased protection from a malicious attack on the network. Additional protection comes from two sources:
1) Executing an attack would be much more expensive.
2) Reduced incentives for attack. The attacker would need to own a near majority of all bitcoin. Therefore, the attacker suffer severely from his own attack.

* When block rewards are produced through txn fees, a proof of stake system would result in lower equilibrium txn fees. Lower long-run fees would increase the competitiveness of bitcoin relative to alternative payments systems. Intuitively reduced fees are due to vast reductions in the scale of wastage of resources.
== The Monopoly Problem ==

If a single entity (hereafter a monopolist) took control of the majority of txn verification resources, he could use these resources to impose conditions on the rest of the network. Potentially, the monopolist could choose to do this in malicious ways, such as double spending or denying service. If the monopolist chose a malicious strategy and maintained his control for a long period, confidence in bitcoin would be undermined and bitcoin purchasing power would collapse. Alternatively, the monopolist could choose to act benevolently. A benevolent monopolist would exclude all other txn verifiers from fee collection and currency generation, but would not try to exploit currency holders in any way. In order to maintain a good reputation, he would refrain from double spends and maintain service provision. In this case, confidence in Bitcoin could be maintained under monopoly since all of its basic functionality would not be affected.

Both benevolent and malevolent monopoly are potentially profitable, so there are reasons to suspect that an entrepreneurial miner might attempt to become a monopolist at some point. Due to the [[Tragedy of the Commons]] effect, attempts at monopoly become increasingly likely over time.

== How Proof of Stake Addresses Monopoly Problems ==

Monopoly is still possible under proof-of-stake. However, proof-of-stake would be more secure against malicious attacks for two reasons.

Firstly, proof-of-stake makes establishing a verification monopoly more difficult. At the time of writing, an entrepreneur could achieve monopoly over proof-of-work by investing at most 10 million USD in computing hardware. The actual investment necessary might be less than this because other miners will exit as difficulty increases, but it is difficult to predict exactly how much exit will occur. If price remained constant in the face of extremely large purchases (unlikely), such an entrepreneur would need to invest at least 20 million USD to obtain monopoly under proof-of-stake. Since such a large purchase would dramatically increase bitcoin price, the entrepreneur would likely need to invest several times this amount. Thus, even now proof-of-stake monopoly would be several-fold more costly to achieve than proof-of-work monopoly. Over time the comparison of monopoly costs will become more and more dramatic. The ratio of bitcoin's mining rewards to market value is programmed to decline exponentially. As this happens, proof-of-work monopoly will become easier and easier to obtain, whereas obtaining proof-of-stake monopoly will become progressively more difficult as more of the total money supply is released into circulation.

Secondly, and perhaps more importantly, a proof-of-stake monopolist is more likely to behave benevolently exactly because of his stake in Bitcoin. In a benevolent monopoly, the currency txn continue as usual, but the monopolist earns all txn fees and coin generations. Other txn verifiers are shut out of the system, however. Since mining is not source of demand for bitcoin, bitcoin might retain most of its value in the event of a benevolent attack. Earnings from a benevolent attack are similar regardless of whether the attack occurs under proof-of-stake or proof-of-work. In a malicious attack, the attacker has some outside opportunity which allows profit from bitcoin's destruction (simple double-spends are not a plausible motivation; ownership of a competing payment platform is). At the same time, the attacker faces costs related to losses on bitcoin-specific investments which are necessary for the attack. It can be assumed that a malicious attack causes the purchasing power of bitcoin to fall to zero. Under such an attack, the proof-of-stake monopolist will lose his entire investment. By contrast, a malicious proof-of-work monopolist will be able to recover much of their hardware investment through resale. Recall also, that the necessary proof-of-work investment is much smaller than the proof-of-stake investment. Thus, the costs of a malicious attack are several-fold lower under proof-of-work. The low costs associated with malicious attack make a malicious attack more likely to occur.

== Why Proof of Stake Would Likely Decrease Long-run Txn Fees Considerably ==
In a competitive market equilibrium, the total volume of txn fees must be equal to opportunity cost of all resources used to verify txns. Under proof-of-work mining, opportunity cost can be calculated as the total sum spent on mining electricity, mining equipment depreciation, mining labor, and a market rate of return on mining capital. Electricity costs, returns on mining equipment, and equipment depreciation costs are likely to dominate here. If these costs are not substantial, then it will be exceptionally easy to monopolize the mining network. The fees necessary to prevent monopolization will be onerous, possibly in excess of the 3% fee currently charged for credit card purchases. Under pure proof-of-stake, opportunity cost can be calculated as the total sum spent on mining labor and the market interest rate for risk-free bitcoin lending (hardware-related costs will be negligible). Since bitcoins are designed to appreciate over time due to hard-coded supply limitations, interest rates on risk-free bitcoin-denominated loans are likely to be negligible. Therefore, the total volume of txn fees under pure proof-of-stake will just need to be just sufficient to compensate labor involved in maintaining bandwidth and storage space. The associated txn fees will be exceptionally low. Despite these exceptionally low fees, a proof-of-stake network will be many times more costly to exploit than the proof-of-work network. Approximately, a proof-of-work network can be exploited using expenditure equal to about one years worth of currency generation and txn fees. By contrast, exploitation of a proof-of-stake network requires purchase of a majority or near majority of all extant coins.

= Implementation =
There are currently a few distinct proposals on how to implement PoS

== Cunicula's Implementation of Mixed Proof-of-Work and Proof-of-Stake ==

This suggestion is of a mixed Proof-of-Work / Proof-of-Stake system.

=== Cunicula's Note ===
Check the page history for the older implementation. I am replacing my description with a new system which I believe to be much more secure. The new system is a greatly improved version of Coblee's Proof of Activity [https://bitcointalk.org/index.php?topic=102355.0 proposal]. It provides extremely strong protection against PoW attacks, both double-spends and denials of service. It is not vulnerable even if PoW attackers also have substantial (but non majority) stake. It provides strong incentives to maintain full nodes. The system is supported through taxes on coin owners who fail to maintain full nodes. Tax revenue is redistributed to coin owners who maintain full nodes. The maintenance of full nodes is the key element providing security in the system.

The discussion focuses on long-term maintenance of the system. Initial distribution of coins could occur through PoW mining, an IPO mechanism, or a more complex scheme that allows initial coins to be distributed to both PoW miners and businesses voted for by coin owners. The issue of initial distribution is separate from long-term maintenance and it is confusing to discuss the two together.

=== Glossary ===
Voluntary Signatures - Voluntary signatures result from a random auditing processes. As blocks are mined, keys are selected for auditing based on random selection. The signatures provide public evidence that a public key owner is running a full node. Passing the audit allows a private key to remain active.

Active Keys - By default, public keys that appear in the blockchain are active if they have a balance of at least one full coin. Public keys that provide voluntary signatures when randomly audited remain active. Active public keys are eligible to participate in lotteries to sign PoW blocks and mine PoS blocks. This is remunerative. Public keys that fail to provide signatures become dead private keys.

Dead Keys - Keys that have failed to provide signatures lose lottery eligibility. Keys that have balances of less than 1 coin are considered dead by default. Dead keys can no longer mine PoS blocks. However, these dead keys can still be used to generate txns. Network maintenance is supported primarily through mandatory fees levied on coins sent by dead keys. After coins are sent using a dead key, the key becomes active provided that it retains a balance of at least 1 coin.

Mandatory Signature Sequence - In order for a PoW block to be valid and enter the blockchain, it must be signed by a sequence of 5 randomly selected active keys. The fifth signatory in the sequence mines a PoS block.

PoS block - The fifth signatory of a PoW block must mint his own block without any PoW submission at all. This block is called a PoS block.

Coin-age - Coin age refers to the age of txn inputs. Coin age is equal to the number of coins sent times the average age on these coins. Age is measured in blocks. Age is reset to 1 block whenever a coin is sent AND whenever a coin provides a signature (both mandatory and voluntary signatures count). Coin-age is used to calculate mandatory fees.

Demurrage Fee - Chain Security is supported primarily through a demurrage tax on sent inputs. This tax proportional to average input age as measured in coin-years. I suggest 5% per coin-year as a reasonable fee. Active keys can avoid demurrage fees simply by remaining active. Thus the actual fee generation will be much lower than 5% per year. Dead keys must pay demurrage. The opportunity to evade demurrage motivates activity.

Optional Fee - Fees are used to ration block space. Blocks select prioritize txns with high fees. If demurrage fees alone are insufficient to motivate txn inclusion, the user can add an optional fee to his txn.

Fee Fund - Both optional fees and demurrage fees enter a fund, rather than being distributed directly to miners. Fees are added to the fund immediately, so there is a weak incentive to include high fee txns in blocks. The PoW miner receives a distribution equal to 0.01% of the accumulated fund. The first four mandatory signatories also receive 0.1% each. The PoS block miner receives 0.1% as well, but his takings will differ slightly because the fund is updated based on txns included in his block. Use of a fund reduces volatility in mining reward.

Root Private Key - The root private key has full spending and signing authority. When significant balances are held, this key should be kept as an offline backup to guard against theft.

Stake Signing Key - Private Key can delegate signing and sending authority to one other private key. The delegated key can sign blocks and has limited authority to send coins. Authority to send coins is determined by two positive constants, t and k. The following txn rule limits the stake signing keys' spending authority:

Change Returned to Public Key >= all coins sent to other addresses * {max(k,k*(t/coin-years on public key)}
k=9 and t=1/12 are suggested as possible parameters. These parameters allows the stake signing key to spend up to 10% of the total key balance per month. The max value at risk in event of theft of
this key is 10%. Holders of large balances 'zero-out' their coin-age frequently via mining and face less theft risk. If this occurs once per week, for example, the large balance holder will only
risk be able to spend up to 2.3% of their balance per week and will only lose 2.3% in the event of theft. Once theft is detected, all remaining coins can be moved to a secure computer using the
root private key.

=== Mining Process ===

1) Block meeting work difficulty target is mined. Difficulty target periodically adjusted so that 1 PoW block arrives every 10 minutes.

2) Work submission is hashed 10 times consecutively. Each consecutive hash maps to an individual unspent output in the blockchain. This is essentially a lottery drawing two sets of five winners. The first five hashes map to mandatory signatures, the final five hashses map to voluntary signatures.

3) If the mandatory signatures map to active public keys [see glossary], the block can potentially be valid. Otherwise, the block is invalid and must be discarded.

4) If PoW miner finds a potentially valid block, he transmits the following hash to the network: {work submission;hash(his block, the previous valid block)}

5) If the work submission meets the difficulty target and maps to active signatories, then the block is relayed through the network. Otherwise, the message is dropped as spam.

5) The first five selected signatories sequentially sign this hash and transmit it onwards as {work submission; hash; sig 1; sig 2; sig 3; sig 4; sig 5}

6) After the mandatory signature sequence is complete, the final signatory publishes the PoW block and also his own PoS block.

7) The final five hashes map to voluntary signatures. These voluntary signatures can be inserted into any block within the next 6 blocks as special txns. These txns do not require fees.

9) Go to step 1

Note: This process is simultaneous so that multiple block hashes can circulate in the network attempting to collect five signatures and generate PoW/PoS block pairs. Block pairs that lose this race
are orphaned.

=== Infeasability of standard attack vectors ===

Unless attackers own a large share of stake, all types of PoW attacks are computationally infeasible. I think there are two types of known attacks: 1) Double-Spend 2) Denial of Service
I consider approximations below. The numbers are so favorable that consideration of exact statistics is not particularly interesting.

1) Double Spend.

Double spends rely on secrecy. In order to mine blocks in secret a PoW miner must select his 5 of his own public keys in the lottery. If the PoW miner owns a share 0<s<1 of all coins,
the probability of doing that a block meeting the difficulty target will select the miner's coins is (1/s)^5. For s=0.01, 1 out of 10 billion blocks will satisfy this criteria.
Even for extremely small hash aggregate rates, it is not practical to privately mine at a rate 10 billion times faster than all other miners combined. For s=0.1, 1 out of 100,000 blocks will
satisfy this criteria. (i.e. the attack still requires approximately 99.999% of all hashing power). For s=0.5, the attacker will succeed if he controls 51% of the aggregate hash rate.

2) Denial of Service

An attacker who mines publicly could simply produce empty PoW blocks. However, this would fail to deny service. 50% of all blocks are randomly mined via PoS. The attacker cannot
force the PoS miners to produce empty blocks. Therefore he cannot deny service regardless of how much hash rate he controls.

=== Long-term Chain Evaluation ===
1) Comparison of two long chains is based on a simple sum of block difficulty, just as in bitcoin.

2) A criticism of PoS is that there is no reason not to sign attack chains. However, in a long secret chain, many stakeholders will have dead signatures. These dead stakeholders will not be able to sign the main chain, but not the attack chain. They will have a strong incentive to make sure the main chain wins because the attack chain will impose demurrage fees on them.

=== Incentives to maintain full nodes ===

This system introduces powerful incentives to maintain full nodes. Many people argue that the lack of an incentive to maintain a full node is a problem in the bitcoin system.

1) a steady flow of txns will generate some fees even if all public keys remain active. Active keys must be maintaining full nodes. Otherwise they could not provide the voluntary signatures which prove their activity. Even very weak incentives are sufficient in this case. If almost all keys are associated with active nodes, then it is not necessary to motivate additional participation.

2) Some public keys may decide to become inactive. This is costly for them. They will suffer a loss of 5% of their balance per year for as long as they remain inactive.

3) The active public keys constantly capture revenue from inactive public keys. This means that the incentives to remain increase dramatically as participation falls. Suppose that 50% of public keys maintain full nodes, then this 50% will capture 2.5% of coins per annum. This is equal to an annual of return of 2.0%. The alternative, inactivity, yields an annual return of -5.0% as discussed in point 2. I consider this a reasonable incentive level and participation rate. Suppose that I am wrong, and only 10% of public keys maintain full nodes. Then these 10% will capture 4.5% of all extant coins per annum. This implies an annual return on participation equal to 45% per annum. This is a very strong incentive and is almost certain to be sufficient, even if nodes are quite costly to maintain. If only 1% of coins participate, then 4.95% of all extant coins will be distributed to this 1% each year. This implies a weekly return on participation of 3%, a pirate ponzi scheme level return. If these incentive are inadequate to support a healthy network of full nodes (which seems unlikely to me), then the levy on dead coins could be increased to exceed 5% per annum.

4) Many people will not have enough coins to justify running their own node. Such individuals will likely use an online banking service which could store their limited spend key. The service could return interest to users in exchange for managing their keys.

5) Other individuals may prefer the privacy associated with dropping out of participation. These individuals are still welcome to use the network, but must face a wealth tax of 5% per annum to compensate for the security risk created by their behavior.

=== Storage of Blockchain Metadata ===
To facilitate the system, data should be extracted from the block chain in a readily accessible database that is updated with each block. The database only needs to incorporate
public keys which control at least 1 coin. Keys with balances less than 1 coin are considered dead by default. These low-value public keys
are not allowed to create limited stake public keys. If a public key balance drops below 1 coin, the limited stake public key associated with the root key is invalidated.

The database would look like this:

{| class="wikitable"
|-
! Public Key (ordered list) !! Linked Stake Public key (if any) !! Balance !! Cumulative Balance !! Active? !! Coin-age (in years)
|-
| A || As || 1 || 1 || 1 || 0.03
|-
| B || Bs || 2.5 || 3.5 || 0 || 0.1
|-
| C || Cs || 3 || 6.5 || 1 || 0.2
|-
| ... || ... || ... || ... || ... || ...
|}
The block chain must maintain records of links between public keys and delegated limited stake public keys. These should be put in a simple database for easy access.

Cumulative balance can be used to determine the winners of the lottery. (i.e. the lottery is a uniform draw on the support [0,total issued coins]) This indicates a unique lottery winner,
whose chance of winning is proportional to his ownership share.

Coin-age is updated as follows.
If no send, Coin-age_t = Coin-age_t-1 + 1.
If send, Coin_age_t = 1.
If send and receipt of coins, Coin_age_t = 1.
If receipt of coins but no send, Coin_age_t = [Coin_age_(t-1)*balance_(t-1)+received coins]/balance(t)

Coin-age is necessary to determine mandatory demurrage fees and to calculate spending limits for limited stake public keys.

Active is 1 by default and becomes 0 if a key fails to provide a requested voluntary signature. 0 is an absorbing state.

=== Beneficiaries and Lossers from Txn Fees ===
The total amount of demurrage fees collected annually varies between 0% and 5% of the total money supply.

The most burdensome fee in the system is the fee paid to PoW miners. This fee imposes a demurrage tax of between 0% and 0.1% per annum on all users of the system. In addition to the demurrage tax, PoW miners receive a 2% share of any optional fees paid to access scarce block space. All coin owners are net losers as a result of PoW mining fees. To minimize costs to coin owners, PoW fee payments are kept as low as possible. Since large hash rates play only a tiny role in security, larger fees for PoW miners are unnecessary.

Other demurrage fees are transfers of revenue from one private key to another. Some keys are net beneficiaries of these transfers, while other keys are net losers. Collectively, these fees do not make coin owners better or worse off. Their effects are neutral. However, individually, the fees do create winners and losers. ''Active'' users that spend infrequently gain from the system. An ''active'' user with average spend frequency is likely to gain from the system as well, but only by a small amount. An ''active'' user that spends very frequently will probably lose from the system. ''Dead'' users will certainly lose from the system. This loss serves as a punishment for failure to maintain an ''active'' node.

== Meni's implementation ==
This proposal is for a proof-of-work (PoW) skeleton on which occasional checkpoints set by stakeholders are placed. In one variant, double-spending is prevented by waiting for a transaction to be included in a checkpoint; the variant described here uses cementing to prevent double-spending, and checkpoints to resolve cementing conflicts.

=== Proof of work ===
Miners use their hashrate to find blocks and build the blockchain exactly as with the pure PoW system. They receive any new generated coins from the block; there will be two kinds of transaction fees, one of which is a mining fee given to the miner who finds the block, just like the PoW transaction fees.

=== Signatures ===
One block every 100 blocks (a different number can be used instead) is a signature block. When a signature block is found and confirmed with several subsequent blocks, stakeholders (people who have bitcoins) are expected to sign it by using a private key associated with their address which contains coins to sign the block hash. If there are several blocks of the same height, an address should not sign more than one of them. The signatures are broadcast on the network and included in a future block. For every candidate block, the total weight of all signatures is tallied (the weight of an address is determined mostly by the number of coins in it, as of the last signature block). Stakeholders will be able to collect signature fees when providing a signature, proportionally to their weight.

At the basic level, there are no rules to choosing which of several conflicting blocks to sign, stakeholders should just choose one.

=== Cementing ===
Cementing is a node's reluctance to do a blockchain reorganization. A node will reject any new block found if it contradicts a 6-block deep branch it is already aware of and currently considers valid. That is, once a node receives 6 confirmations for a block, it will not accept a competing block even if it is part of a longer branch.

In a pure PoW system this is problematic to do because a node could be stuck on "the wrong version" - if an attacker isolates the node and feeds him bogus data, it will not embrace the true, longer chain when he learns of it. However, using PoS to have the final say in such situations makes this possible.

=== Branch selection ===
When a node needs to select which of several branches is valid, it chooses one based on the following criteria in increasing importance (each one is overridden by the next):

#Branch length (total difficulty of all blocks), as in a PoW system.
#Cementing - an already cemented block will not be replaced by a longer branch.
#Signatures - even a cemented block will be overridden by a signature block with signature weight more than half the total possible weight by some margin.

If the conflict is so long that it contains more than one spot for a signature block, the conflicting signature blocks will be traversed earliest to latest, each time choosing the branch with the majority vote. After the newest uncontested signature block it proceeds to use cementing and branch length.

A signature block with no clear majority will be considered tied, and will not override the other criteria. Signature fees will not be given out but instead carried over to the next signature spot, to encourage stakeholders to participate then.

=== [[Double-spending]] prevention ===
A good level of security can be achieved by waiting for a block to be cemented. By that time it is safe to assume that the network recognizes this block and will not easily switch to a different block, even if a longer branch is presented.

A more authoritative confirmation is enabled by waiting for a signature block. Once a block achieves a majority (and some more time is allowed for this majority to spread in the network), it is extremely unlikely that the network will ever switch away from this block.

=== Weights ===
The weight of every address starts at 0. When an address provides a signature, its weight increases so that after several signatures, the weight approaches the number of coins in the address as of the last signature block. For example,
New weight = 0.9 * Old weight + 0.1 * Balance
If a signature is not provided by the address in a signature block, its weight decreases:
New weight = 0.9 * Old weight
This way, addresses whose owners do not wish to participate in signing do not hamper the ability to reach a majority.

If an address signs two conflicting blocks, its weight is reset to 0. This is to limit the power of malicious stakeholders.

If coins move to a new address, weight is proportionally taken away from the addressed, but is not transferred to the new address. The new stakeholder will have to build up his weight.

=== Malicious stakeholders ===
The system is resilient against stakeholders who misuse their signature power, even if they have a majority of the bitcoins. Since their only obligation is to not sign conflicting blocks, the only way they could double-spend is if they first sign one block so it achieves a majority, then sign a different one so that it achieves a bigger majority. Generally this will not work. A short while after a majority is achieved, most of the network will be aware of the relevant signatures. If a different signature is broadcast, the conflict will be detected and both signatures will be ignored. This will cause the current majority block to become tied, but the network is already cemented on it and will vote for this branch in the next signature block. The weight of the attacker will by then reduce to 0 so he will be unable to create more disruption.

Another attack is refusing to sign blocks to keep them tied. Since this causes a decay of the weight, they can only stand in the way of a majority for a short time.

=== Denial of service ===
The method as described does not solve a denial of service scenario. A majority miner could create only blocks with no transactions (or with many transactions missing) and reject all other blocks.

This may be solvable by adding some measure of the transaction in a block to the selection criteria, such as Bitcoin days destroyed.

Also, proposals to replace the block chain with a directed acyclic graph have been made, and could be used to make it easier to include transactions.

== Key difference between the two proposals ==
In Cunicula's system, voting power is determined by combining (multiplicatively) your hashrate and stake. This would be problematic if small players could not compete effectively with large players. Though we are waiting on a formal mathematical proof, evidence to date suggests that small and large players would have an equal competitive footing. Simulations described in this thread [https://bitcointalk.org/index.php?topic=68213.msg801253#msg801253] indicate that small players are competitive with large players because the multiplicative combination of hashrate and stake exhibits constant returns. Evidence in the thread suggests that these simulation results are accepted by both Cunicula and Meni.)

In Meni's, there's a skeleton based purely on hashrate, and superimposed on it are occasional checkpoints set by stakeholders. You can contribute PoW without having stake, and you can contribute PoS without having work, and in both cases your voting power and reward is linearly proportional to the resources you have.

== PPCoin ==
[http://ppcoin.org PPCoin] is the first known implementation of a combined PoS/PoW system (released August 19 2012).

== See also ==
*[[Proof_of_work|Proof of work]]
*[[Proof_of_burn|Proof of burn]]

[[category:mining]]

User:Sahtor

2014-04-01T19:09:56Z

Sahtor:

==Contact==
* email: sahtor@sahtor.net
* web: https://sahtor.net

User:Sahtor

2011-12-13T13:11:10Z

Sahtor:

Contributors Award participant: 19aG8DHbv7KHjoHYP4Ms75cDDwve7YfP63

==Contact==
* email: sahtor@gmail.com
* Twitter: [http://twitter.com/Sahtor @Sahtor]

Bitcoin.org translations

2011-03-01T17:41:28Z

Sahtor: /* Finnish */ more precise copy of english

This is a translation template for the [http://bitcoin.org bitcoin.org] front page. All translations should be updated to match the English page. The download links aren't included because updating every translation after every release is a pain in the butt. The page is nicer to edit when you click "edit" on a subsection.

==English==
All translations should be updated to match this.

<source lang="html4strict"><i>If you have version 0.3.9 or lower, please upgrade for an important security update!</i>

<h2 class="homepage-title page-title">Bitcoin P2P Virtual Currency</h2>

Bitcoin is a peer-to-peer digital currency. Peer-to-peer (P2P) means that there is no central authority to issue new money or keep track of transactions. Instead, these tasks are managed collectively by the nodes of the network. Advantages:

<ul>
<li>Bitcoins can be sent easily through the Internet, without having to trust middlemen.</li>
<li>Transactions are designed to be irreversible.</li>
<li>Be safe from instability caused by fractional reserve banking and central banks. The limited inflation of the Bitcoin system’s money supply is distributed evenly (by CPU power) throughout the network, not monopolized by banks.</li>
</ul>

Bitcoin is an open source project currently in beta development stage. Development is hosted at <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.

Screenshots:

<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a></p>

Using Bitcoin:

For the first hour or two the block count will increase rapidly as the block chain is received.

Turn on Options->Generate Coins to contribute your idle CPU time to the network. Bitcoin runs in the background when your computer is idle and should not slow down other programs.

The total eventual circulation will be 21 million bitcoins. There will never be more coins than that. The coins are entering circulation gradually, at a steady pace over many years, to nodes supporting the network in proportion to the CPU time they contribute. With the current total CPU power on the network, most CPUs will usually take months between successfully generating 50 BTC.

You can get a few free bitcoins from the <a href="http://freebitcoins.appspot.com/">Bitcoin Faucet</a>. If Bitcoin is running when you receive a transaction, you can see it immediately, otherwise it may take 10 minutes or more after it was sent, and all blocks need to have finished downloading. As of December 2010, there are 97000 blocks.

To receive incoming connections, set your firewall to forward port 8333 (TCP) to your computer. This increases the number of nodes you can connect with.
</source>

==Russian==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin: P2P-криптовалюта</h2>

Bitcoin - это основанная на системе peer-to-peer цифровая валюта. Использование системы peer-to-peer (P2P) обозначает, что в данной системе нет центральной власти, которая выдает новые деньги или записывает все транзакции. Вместо этого, эти задачи выполняются коллективно всеми узлами сети. Выгоды этого подхода:

<ul>
<li>Простая передача денег через интернет, без необходимости доверять посредникам.</li>
<li>Третьи лица не могут предотвратить или контролировать ваши транзакции.</li>
<li><strong>Переводы денег посредством Bitcoin практически бесплатны</strong>, в то время как кредитные карты и системы онлайновых платежей обычно требуют комиссию в 1-5% суммы каждого перевода + дополнительные торговые затраты, (которые могут достигать несколько сот долларов).</li>
<li>Отсутсвтие нестабильности, которую вызывают банковская мультипликация (fractional reserve banking) и политика центральных банков. Ограниченная инфляция денежной поддержки в системе Bitcoin распределяется поровну (по мощности процессора) через всю сеть, а не монополизируется банками.</li>
</ul>

Bitcoin - это проект с открытыми исходниками (open source), созданный Сатоши Накамото. Данный проект сейчас находится в стадии beta. Разработка Bitcoin обеспечивается сервисом <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.

Скриншоты:

<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a></p>

Использование Bitcoin:

Включите флажок Options->Generate Coins, чтобы получить некоторое количество монет, в то же время помогая работе сети. Bitcoin запускается в фоновом режиме и работает в то время, когда ваш компьютер простаивает, и следовательно не должен замедлять работу других программ. "Генерация" монеты может затратить до нескольких дней, так что будьте терпеливы. Требуемое время зависит от того, сколько времени простоя вашего процессора вы затрачиваете.

Итоговая циркуляция (количество) денег в системе Bitcoin будет равно 21 000 000 монет. Дальше этой суммы монеты создаваться не будут. Монеты входят в циркуляцию постепенно в течение множества лет, раздаваясь узлам, поддерживающим сеть пропорционально затрачиваемому ими процессорному времени.

Для того, чтобы получать входящие соединения, вам может понадобиться настроить ваш брандмауэр(firewall) для перенаправления порта 8333 (по протоколу TCP) на ваш компьютер. Таким образом вы можете увеличить количество узлов, с которыми сможете соединиться.

Bitcoin может быть использован с Tor при использовании командной строки:
bitcoin -proxy=127.0.0.1:9050

Если вы хотите остаться анонимным, будьте осторожны: не раскрывайте информацию, которая может связать ваши адреса Bitcoin с вашей личностью и используйте отдельный адрес Bitcoin для каждого платежа, который вы получаете.
</source>

==Spanish==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin P2P Criptodivisa</h2>

Bitcoin es una red punto a punto (P2P) basada en una divisa digital. Punto a punto (P2P) significa que no hay una autoridad central que emita nuevo dinero o registre las transacciones. Sin embargo, estas tareas son realizadas colectivamente por los nodos de la red. Ventajas:

<ul>
<li>Transferir dinero facilmente mediante Internet, sin tener que confiar en intermediarios.</li>
<li>Terceros no pueden prevenir o controlar sus transacciones.</li>
<li><strong>Las transacciones de Bitcoin son practicamente gratuitas</strong>, mientras que los sistemas de pago online o con tarjetas de credito cuestan entre un 1-5% adicional junto con otras comisiones adicionales, elevando la cantidad de dinero a pagar.</li>
<li>Permanezca a salvo de la inestabilidad causada por las reservas bancarias y las malas politicas de los bancos centrales. La inflación limitada de la oferta monetaria del sistema Bitcoin se distribuye de manera uniforme (por CPU) a través de la red, no monopolizada por los bancos.</li>
</ul>

Bitcoin es un proyecto open source creado por Satoshi Nakamoto, y actualmente se encuentra en un estado beta de desarrollo. El desarrollo de Bitcoin se encuentra en <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.

Capturas de pantalla:

<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Captura de la ventana principal" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Captura del dialogo de envio" /></a></p>

Usando Bitcoin:

Entre en Opciones->Generar monedas para conseguir unas cuentas mientras ayuda a expandir la red. Bitcoin se ejecuta en segundo plano cuando su ordenador no tiene tareas y no deberia ralentizar otros programas. Puede tardar dias en generar un moneda satisfactoriamente, sea paciente. El tiempo varia y depende de los tiempos de CPU con los que usted contribuya.

El total de monedas en circulacion en Bitcoin sera de 21.000.000 monedas. Nunca habra un numero superior a este. Las monedas entran en circulacion de manera gradual, a un ritmo constante, en los nodos en proporcion al tiempo de CPU con el que contribuyen.

Para recibir conexiones entrantes, necesita configurar su firewall para redirigir el puerto 8333 (TCP) a su ordenador. Esto incrementa el numero de nodos a los que se puede conectar.

Bitcoin puede usarse mediante Tor con la linea de comandos:
bitcoin -proxy=127.0.0.1:9050

Si desea permanecer en el anonimato (bajo seudonimo, en realidad), tenga cuidado de no revelar ninguna informacion que vincule su direccion Bitcoin a su identidad, y utilice una direccion Bitcoin nueva por cada pago que usted reciba.
</source>

==German==
<source lang="html4strict">
<h2 class="homepage-title page-title">Die Bitcoin P2P Krypto-Währung</h2>

Bitcoin ist eine digitale Währung, die auf einem Peer-to-Peer-Netzwerk aufbaut. Peer-to-Peer (P2P) bedeutet hier, dass es keine zentrale Autorität gibt, welche dafür zuständig ist neues Geld in Umlauf zu bringen oder den Zahlungsverkehr zu regeln. Stattdessen werden diese Aufgaben kollektiv von den Teilnehmern des Netzwerkes übernommen.

Vorteile:

<ul>
<li>Man kann Geld einfach per Internet überweisen, ohne sich auf Banken oder andere Dienstleister verlassen zu müssen.</li>
<li>Überweisungen können von Dritten nicht kontrolliert oder verhindert werden.</li>
<li><strong>Bitcoin-Überweisungen sind praktisch kostenlos</strong>, während man bei Kreditkarten und Online-Zahlungssystemen normalerweise 1-5% der Überweisungssumme als Gebühr bezahlt.</li>
<li>Man vermeidet die Instabilitäten, die durch das partielle Reservesystem und schlechte Entscheidungen der Zentralbanken verursacht werden können. Die begrenzte Inflation der Geldmenge im Bitcoin-System findet dezentral und gerecht (nach Prozessor-Leistung verteilt) im ganzen Netzwerk statt, anstatt zentral, von den Banken allein, bestimmt zu werden.</li>
</ul>

Bitcoin ist ein Open-Source-Projekt, das von Satoshi Nakamoto ins Leben gerufen wurde. Es wird auf <a href="http://sourceforge.net/projects/bitcoin/">Sourceforge</a> entwickelt und befindet sich derzeit in der Beta-Phase.

Screenshots:

<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Screenshot des Programmfensters" /></a></p>

<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Screenshot des Überweisungsfensters" /></a></p>

Bitcoin verwenden:

Aktivieren Sie im Menü Options->Generate Coins um ein paar Münzen zu verdienen indem Sie dabei helfen das Netzwerk am laufen zu halten. Bitcoin läuft im Hintergrund während der eigene Computer sich im Leerlauf befindet und sollte andere Programme nicht verlangsamen. Abhängig davon, wie viel Rechenzeit Sie beitragen können, kann es einige Tage dauern bis die ersten Münzen erzeugt werden – haben Sie also bitte etwas Geduld.

Insgesamt wird es am Schluß 21.000.000 Münzen geben. Das ist eine harte Obergrenze, die nicht überschritten wird. Die Münzen werden über Jahre hinweg nach und nach in Umlauf gebracht: Sie werden an die einzelnen Teilnehmer ausgeschüttet, proportional zu der Menge Rechenzeit die diese beitragen.

Um eingehende Verbindungen empfangen zu können, müssen Sie evtl. Ihre Firewall oder Ihren Router so einstellen, dass Port 8333 (TCP) weitergeleitet wird. Dadurch erhöht sich die Anzahl der anderen Teilnehmer, mit denen Sie Verbindung aufnehmen können.
</source>

==Italian==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin P2P Cryptomoneta</h2>
Bitcoin e una moneta digitale basata su network peer-to-peer. Peer-to-peer (P2P) significa che non c'è un'autorita centrale che rilasci nuova moneta o che tenga traccia dei trasferimenti. In questo caso invece, queste operazioni sono gestite collettivamente dai nodi del network. Vantaggi:

<ul>
<li>Trasferire soldi facilmente attraverso Internet, senza aver bisogno di trovare e fidarsi di intermediari.</li>
<li>Enti terzi non potranno prevenire o controllare i vostri trasferimenti</li>
<li><strong>I trasferimenti di Bitcoin sono praticamente gratuiti</strong>, dove invece carte di credito o altri sistemi di pagamento online costano tipicamente il 1-5% per operazione, più altri costi aggiuntivi dell'ordine di centinaia di euro.</li>
<li>Si trova al riparo dall'instabilità delle riserve bancarie frazionate e dalle cattive politiche fatte dalle banche centrali. La limitata inflazione del sistem Bitcoin è distribuita uniformamente ( dal calcolo delle CPU ) attraverso il network, senza essere monopolizzata dalle banche.</li>
</ul>

<p>Bitcoin è un progetto open source creato da Satoshi Nakamoto, e si trova attualmente nello stato di sviluppo di beta. Le sorgenti di Bitcoin sono mantenute dall'hosting fornito da <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.

Immagini:
<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot"/></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a> </p>

Usare Bitcoin:
<p>Dovete andare ad attivare l'opzione <b>Options->Generate Coins</b> per ottenere alcune monete ( coins ) per aver aiutato a mantenere il network. Bitcoin lavora in background quando il computer è fermo e non dovrebbe rallentare l'uso di altri programmi. Potrebbe richiedere giorni per generare correttamente una moneta ( coin ), quindi siate pazienti. Questo tempo può variare e dipende anche da quanto contibuirete offrendo la vostra CPU.</p>

Il massimo possibile di Bitcoin in circolazione sarà 21,000,000. Non ci sara mai una quantità maggiore di moneta oltre a questa. Queste monete ( coins ) entrano in circolazione gradualmente, per un ritmo costante di diversi anni, basato dai nodi che parteciperanno al network e dall'uso delle loro CPU.

Per poter ricevere le connessioni in entrata, dovrete impostare il vostro firewall/router per aprire la porta 8333 ( TCP ) del vostro computer. Questo aumenterà il numero di nodi a cui riuscirete a connettervi.
</source>

==French==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin, cryptodevise en pair-à-pair</h2>

<p>Bitcoin est une devise électronique basée sur un réseau de type peer-to-peer. Peer-to-peer (P2P) signifie qu'il n'existe pas d'autorité centrale habilitée à émettre de la monnaie ou à tenir un journal des transactions. Au lieu de cela, ces tâches sont gérées de façon collective par l'ensemble des noeuds du réseau. Parmi les avantages :</p>
<ul>
<li>Les transfers peuvent être effectués facilement via Internet, sans avoir à passer par un tiers de confiance.</li>
<li>Aucun tiers ne peut empêcher ou contrôler vos transactions.</li>
<li><strong>Les transactions par Bitcoin sont quasiment gratuites</strong>, tandis que les cartes de crédit et autres moyens de paiement en ligne coutent typiquement de 1 à 5% par transaction, sans compter divers prélèvements effectués par les marchands, qui peuvent s'élever à plusieurs centaines de dollars.</li>
<li>Le système est à l'abri de l'instabilité causée par le système des réserves fractionnaires ainsi que par les mauvaise politiques monétaires des banques centrales. L'inflation limitée du système Bitcoin est distribuée de façon homogène (par puissance de calcul [CPU]) à travers le réseau, et non monopolisée par les banques.</li>
</ul>
<p>Bitcoin est un projet logiciel libre créé par Satoshi Nakamoto, actuellement en phase de développement béta. Le développement de Bitcoin est hébergé par <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.</p>

<p>Screenshots:</p>
<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a></p>
<p>Utilisation de Bitcoin:</p>
<p>Activez l'option "Option->Generate Coins" afin d'obtenir des pièces en aidant au fonctionnement du réseau. Bitcoin tourne en arrière-plan lorsque l'ordinateur est inactif et il ne devrait pas ralentir vos programmes. La génération d'un bitcoin peut prendre plusieurs jours, soyez-donc patient. La durée exacte dépend de la quantité de temps CPU que vous pouvez apporter. </p>
<p>Le nombre total de bitcoins en circulation sera à terme de 21 millions. Il n'y aura jamais plus de bitcoins que cela. Les bitcoins entrent en circulation graduellement, à un rythme constant pendant de nombreuses années, vers les noeuds supportant le réseau et en proportion du temps CPU qu'il procurent.</p>
<p>Pour recevoir des connexions entrantes, vous devez configurer votre pare-feu afin de lui faire rediriger le port TCP 8333 vers votre machine. Cela améliore le nombre de noeuds avec lesquels vous pouvez vous connecter.</p>
<p>Bitcoin peut être utilisé en conjonction avec Tor grâce à la commande suivante :<br />
bitcoin -proxy=127.0.0.1:9050</p>
<p>Si vous essayez de garder l'anonymat (pseudonymat, pour être exact), prenez garde de ne pas révéler d'information permettant de relier votre adresse bitcoin à votre identité. Vous devriez utiliser une adresse bitcoin différente pour chaque paiement que vous recevez.</p>
</source>

==Finnish==
<source lang="html4strict">
<i>Jos käytät versiota 0.3.9 tai vanhempaa, Päivitä tärkeän turvallisuuspäivityksen vuoksi!</i>

<h2 class="homepage-title page-title">Bitcoin P2P Digivaluutta</h2>

Bitcoin on vertaisverkkoon perustuva digitaalinen valuutta. Vertaisverkkoon (peer-to-peer network) perustuva toiminta tarkoittaa sitä, että mikään keskitetty taho ei hallinnoi rahan liikkeellelaskua tai maksutapahtumia, vaan verkon tietokoneet hoitavat nämä tehtävät kollektiivisesti. Etuja:

<ul>
<li>Siirrä rahaa helposti Internetin ylitse ilman välikäsiä.</li>
<li>Maksutapahtumat on suunniteltu olemaan peruuttamattomia.</li>
<li>Suojaudu osittaisen kassavarannon pankkijärjestelmän aiheuttamalta epävakaudelta ja keskuspankkien huonolta rahapolitiikalta. Bitcoin-rahakannan rajallinen kasvu jakautuu tasaisesti (käytetyn prosessoriajan mukaan) koko verkkoon, ei keskitetysti pankeille.</li>
</ul>

Bitcoin on avoimen lähdekoodin projekti, joka on tällä hetkellä betakehitysvaiheessa. Projektin kehityssivut ovat <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>:ssa.

Kuvia:

<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a></p>

Ohjelman käyttö:

Ensimmäisten tuntia aikana blokkien määrä nousee nopeati kunnes koko blokkiketju on vastaanotettu.

Valitse Options->Generate Coins niin osallistut verkon pyörittämiseen ja saat itsellesi kolikoita. Ohjelma käyttää prosessoria silloin kun muut ohjelmat eivät, joten muiden ohjelmien toiminnan ei pitäisi hidastua.

Bitcoineja tulee aikanaan olemaan yhteensä 21 miljoonaa. Sen enempää rahaa ei koskaan tule. Rahamäärä tulee kiertoon asteittain, tasaiseen tahtiin useiden vuosien aikana, ja jakautuu verkon tietokoneille suhteessa niiden lahjoittamaan prosessoriaikaan. Nykyisen verkon prosessoreiden kokonaistehon vuoksi useimmat koneet tarvitsevat useita kuukausia 50 BTC:n luomisen onnistumiseen.

Voit saada muutaman ilmaisen bitcoinin <a href="http://freebitcoins.appspot.com/">Bitcoin Faucet</a> sivulta. Jos Bitcoin on päällä kun vastaanotat maksutapahtuman näet rahan reaaliaikaisesti. Muussa tapauksessa saattaa kestää 10 minuuttia tai kauemmin kunnes kaikki koneet ovat vastaanottaneet tapahtuman. Joulukuussa 2010 verkossa oli 97000 blokkia.

Sisääntulevien yhteyksien vastaanottamiseksi porttiin 8333 (TCP) saapuvien yhteyksien tulee reitittyä koneellesi. Tämä lisää niiden verkon koneiden määrää, joihin voit olla yhteydessä.
</source>

==Swedish==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin P2P Cryptocurrency</h2>

Bitcoin är en digital valuta baserad på peer-to-peer-nätverk. Peer-to-peer (P2P) innebär att det inte finns någon central myndighet som utfärdar nya pengar eller håller reda på transaktioner. Istället sköts dessa uppgifter kollektivt av noderna i nätverket. Fördelar:

<ul>
<li>Överför pengar enkelt via Internet, utan att behöva lita på mellanhänder.</li>
<li>Tredje part kan inte förhindra eller kontrollera dina transaktioner.</li>
<li><strong>Bitcoin transaktioner är praktiskt taget gratis</strong>, medan kreditkort och online-betalningssystem normalt kostar 1-5% per transaktion plus diverse andra handelsavgifter upp till hundratals dollar.</li>
<li>Skydd från den instabilitet som orsakas av fractional-reserve banking och centralbankernas dåliga politiker. Den begränsade inflationen av Bitcoin-systemets penningsmängd fördelas jämnt (enligt processorkraft) över hela nätet i stället för att den skulle monopoliseras av bankerna.</li>
</ul>

Bitcoin är ett open source -projekt skapat av Satoshi Nakamoto, och är för tillfället i betastadiet. Bitcoin-utvecklingen finns på <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.

Bilder:

<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a></p>

Använding av Bitcoin:

Välj Options -> Generate coins för att få några slantar genom att hjälpa driva nätverket. Bitcoin körs i bakgrunden när datorn är inaktiv och så borde inte försena andra program. Det kan ta dagar att generera ett bitcoin, så ha tålamod. Tiden varierar och beror på hur mycket processortid du använder.

Till sluts kommer det att finnas 21 000 000 bitcoins. Det kommer aldrig att finnas fler bitcoins en så. Mynten kommer i cirkulation gradvis, med jämn takt under många år, till noder som stödjer nätverket (i proportion till den processortid de använder).

För att ta emot inkommande anslutningar, måste du ställa in din brandvägg att vidarebefordra port 8333 (TCP) till din dator. Detta ökar antalet noder du kan ansluta med.
</source>

==Norwegian / Norsk==
<source lang="html4strict">
<h2 class="homepage-title page-title"> Bitcoin P2P Kryptovaluta </h2>

Bitcoin er en digital valuta basert på peer-to-peer-nettverk. Peer-to-peer (P2P) betyr at det ikke er noen sentral myndighet som utsteder nye penger eller holder oversikt over transaksjoner. I stedet forvaltes disse oppgavene kollektivt av nodene i nettverket. Fordeler:

<ul>
<li> Overfør penger enkelt via Internett, uten å måtte stole på mellommenn. </li>
<li> Tredjeparter kan ikke hindre eller kontrollere transaksjoner. </li>
<li> <strong> Bitcoin-transaksjoner er nesten gratis </strong>, mens kredittkort og elektroniske betalingssystemer vanligvis koster 1-5% per transaksjon, pluss andre diverse avgifter for handele på opp til flere hundre dollar. </li>
<li> beskyttelse mot ustabilitet forårsaket av fractional-reserve banking og sentralbankers dårlige politikk. Den begrensede inflasjon av Bitcoin-systemets pengebeløp er fordelt jevnt (med CPU-kraft) over Bitcoin-nettverket i stedet for å være monopolisert av bankene. </li>
</ul>

Bitcoin er en åpen kildekode-prosjekt skapt av Satoshi Nakamoto, og er for tiden i beta-fasen. Utviklingen av Bitcoin skjer på <a href="http://sourceforge.net/projects/bitcoin/"> SourceForge </ a>.

Bilder:

<p> href="/sites/default/files/screen3.png"> <img src="/sites/default/files/screen3_thumb.png" alt="Hovedvindu skjermbilde" /> </a> </p>
<p> href="/sites/default/files/screen4.png"> <img src="/sites/default/files/screen4_thumb.png" alt="Sendedialog skjermbilde" /> </a> </p>

Hvordan bruke Bitcoin:

Velg Alternativer -> Generer mynter for å få et par dollar ved å hjelpe vedlikeholde nettverket. Bitcoin kjører i bakgrunnen når datamaskinen er inaktiv, og det bør ikke bremse ned andre programmer. Det kan ta dager å generere en bitcoin, så vær tålmodig. Tiden varierer og avhenger av hvor mye CPU-kraft du bruker.

Etter hvert vil det finnes totalt 21 millioner bitcoins. Det vil aldri være mer bitcoins enn det. Myntene øker i omløp etter hvert og bilr fordelt med en jevn hastighet over mange år til de brukerene som støtter nettverket over tid (med sin CPU-kraft).

For å motta innkommende tilkoblinger, må du stille inn brannmuren til å videresende port 8333 (TCP) til datamaskinen din. Dette øker antall noder du kan få kontakt med.
</source>

==Chinese (simplified)==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin P2P Cryptocurrency</h2>

Bitcoin是点对点(peer-to-peer)基于网络的匿名数字货币。点对点(peer-to-peer)的意思是指没有中央权威控制货币的汇款通道。相反，这些货币转帐的任务是由网络节点进行的集体管理。匿名就意味着交易各方可以隐藏自己的真实身份。优势：

<ul>
<li>无需信托中间人，能够方便的进行互联网上的汇款。</li>
<li>第三方不能够控制或者阻止您的交易。</li>
<li><strong>Bitcoin 交易几乎免费</strong>, 而信用卡的网上在线支付系统通常收取 1-5% 的交易费用，加上其他各种费用高达数百美元。</li>
<li>避免了中央储备银行的不良政策和不稳定性所造成的安全隐患. Bitcoin系统的有限货币通胀是均匀分布(由CPU决定)于整个网络, 而不是由银行垄断.</li>
</ul>

Bitcoin 是一个由Satoshi Nakamoto 制作的开源项目, 目前处于开发测试阶段. Bitcoin 研发网址位于<a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.

截图:

<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot" /></a></p>

<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a></p>

使用 Bitcoin:

在选项(Options)->生成(Generate) 货币(Coins) 获得帮助网络运行的几个货币. Bitcoin 在计算机的后台运行，因此不会影响其他程序的运行. 它可能需要数天时间产生一个货币, 请耐性等待. 随着时间的长短而不同, 你的贡献决定于CPU的空闲挂载时间.

最终的Bitcoins总量将达到21,000,000货币单位，这是货币量的上限. 在支持网络的节点上, 以CPU的负载时间决定他们的贡献量, 这套货币将以稳定的步伐在数年间逐渐进入流通渠道.

如需接受传入连接, 请将您计算机的防火墙映射到8333(TCP) 端口. 此操作将增加您电脑的网络节点连接数.
</source>

==Chinese (traditional)==
<source lang="html4strict">
<h2 class=\"homepage-title page-title\">Bitcoin P2P Cryptocurrency</h2>

Bitcoin是點對點(peer-to-peer)基於網絡的匿名數字貨幣。點對點(peer-to-peer)的意思是指沒有中央權威控制貨幣的匯款通道。相反，這些貨幣轉帳的任務是由網絡節點進行的集體管理。匿名就意味著交易各方可以隱藏自己的真實身份。優勢：

<ul>
<li>無需信托中間人，能夠方便的進行互聯網上的匯款。</li>
<li>第三方不能夠控制或者阻止您的交易。</li>
<li><strong>Bitcoin 交易幾乎免費</strong>, 而信用卡的網上在線支付系統通常收取 1-5% 的交易費用，加上其他各種費用高達數百美元。</li>
<li>避免了中央儲備銀行的不良政策和不穩定性所造成的安全隱患. Bitcoin系統的有限貨幣通脹是均勻分布(由CPU決定)於整個網絡, 而不是由銀行壟斷.</li>
</ul>

Bitcoin 是一個由Satoshi Nakamoto 制作的開源項目, 目前處於開發測試階段. Bitcoin 研發網址位於<a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.

截圖:
<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot"/></a></p>

<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot"/></a></p>

使用 Bitcoin:

在選項(Options)->生成(Generate) 貨幣(Coins) 獲得幫助網絡運行的幾個貨幣. Bitcoin 在計算機的后台運行，因此不會影響其他程序的運行. 它可能需要數天時間產生一個貨幣, 請耐性等待. 隨著時間的長短而不同, 你的貢獻決定於CPU的空閑挂載時間.

最終的Bitcoins總量將達到21,000,000貨幣單位，這是貨幣量的上限. 在支持網絡的節點上, 以CPU的負載時間決定他們的貢獻量, 這套貨幣將以穩定的步伐在數年間逐漸進入流通渠道.

如需接受傳入連接, 請將您計算機的防火牆映射到8333(TCP) 端口. 此操作將增加您電腦的網絡節點連接數.
</source>

==Czech==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin P2P Kryptopeníze</h2>
<p>Bitcoin je měna založena na peer-to-peer sítích. Peer-to-peer (P2P) znamená, že neexistuje žádná centrální autorita pro vydávání nových peněz, nebo sledování transakcí. Místo toho jsou tyto úkoly spravovány kolektivně uzly v síti. Výhody:</p>
<ul>
<li>Transfer peněz jednoduše přes Internet, bez nutnosti věřit prostředníkům.</li>
<li>Třetí strany nemohou zabránit, nebo kontrolovat vaše transakce.</li>
<li><strong>Bitcoin transakce jsou prakticky zdarma</strong>, zatímco kreditní karty a online platební systémy běžně stojí 1-5% za transakci, plus různé další poplatky obchodníkům, až do stovek dolarů.</li>
<li>Uchraňte se před nestabilitou způsobenou špatnou politikou centrálních bank. Omezená inflace peněžních zásob Bitcoin systému je distribuovaná rovnoměrně (silou CPU) skrz síť, nikoliv monopolizovaná bankami.</li>
</ul>
<p>Bitcoin je open source projekt, který vytvořil Satoshi Nakamoto a nyní se nachází v beta vývojovém stádiu. Vývoj Bitcoin je hostován na <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.</p>
<p>Screenshoty:</p>
<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Screenshot hlavního okna" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Screenshot odesílacího dialogu" /></a></p>
<p>Použití Bitcoin:</p>
<p>Zapněte Možnosti->Generovat mince, abyste získali několik mincí a pomohli fungování sítě. Bitcoin běží na pozadí když je váš počítač nečinný a neměl by zpomalovat ostatní programy. Může to trvat dny, než úspěšně vygenerujete minci, takže buďte trpěliví. Načasování závisí na tom, kolik volného času vašeho CPU přispějete. </p>
<p>Celkem by mělo být v Bitcoin systému v oběhu 21 milionů mincí. Nikdy se tam nebude nacházet více mincí. Mince vstupují do oběhu postupně stálým tempem po mnoho let, do uzlů podporujících síť v poměru k času CPU, kterým přispěly.</p>
<p>Pro přijetí přicházejících spojení musíte nastavit svůj firewall na přeposílání portu (port forwarding) 8333 (TCP) na váš počítač. Toto zvýší počet uzlů, se kterými se můžete spojit.</p>
<p>Bitcoin může být používán skrz Tor pomocí příkazové řádky:<br />
bitcoin -proxy=127.0.0.1:9050</p>
<p>Pokud zkoušíte zůstat anonymní (ve skutečnosti pseudoanonymní), buďte opatrní a neprozrazujte žádné informace spojením své Bitcoin adresy se svou identitou. Pro každou platbu kterou obdržíte byste měli použít novou Bitcoin adresu.</p>
</source>

==Polish==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin P2P waluta kryptograficzna</h2>

Bitcoin jest opartą o sieć peer-to-peer (P2P) cyfrową walutą. Peer-to-peer (P2P) gwarantuje, że nie ma centralnej instytucji która miałaby wpływ na nowe pieniądze oraz nikt nie może śledzić tranzakcji. Rolę tej instytucji przejmują węzły sieci które współpracują wspólnie w sieci.
Zalety:

<ul>
<li>Transfer pieniędzy przez sieć jest łatwy i prosty, bez ingerencji osób trzecich (np. Banków)</li>
<li>Osoby trzecie nie mogą zapobiec ani kontrolować tranzakcji</li>
<li>Tranzakcje Bitcoin są praktycznie bezpłatne , podczas gdy karty kredytowe oraz płatności online zazwyczaj kosztują od 1 – 5% od tranzakcji plus inne dodatkowe opłaty manipulacyjne nawet to kilkuset dolarów</li>
<li>Jesteś zabezpieczony przed niestabilnością rezerw banków oraz złej polityki banków centralnych. Ograniczona inflacja systemu monetarnego Bitcoin oraz równomierna dystrybucja pieniądza (przez moc CPU) w obrębie sieci bitcoin, nie zmonopolizowana przez banki.</li>
</ul>

Bitcoin jest projektem open source stworzonym przez Satoshi Nakamoto, a obecnie jest na etapie rozwoju. Rozwianie projektu jest wspierane przez SourceForge.

Zrzuty ekranu:
<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a></p>

Jak używać bitcoin:

Przejdź do Options->Generate Coins by wygenerować kilka monet oraz wspierać działanie sieci. Bitcoin działa w tle kiedy twój komputer jest w stanie bezczynności i nie powinien spowalniać innych programów. Generowanie bitcoin może zająć wiele dni, więc musisz uzbroić się w cierpliwość. Czas generowania może być różny i zależeć od tego ile czasu procesora jest efektywnie wykorzystane. Docelowo całkowita ilość pieniędzy w obiegu nie przekroczy 21 milionów i nigdy nie będzie więcej monet powyżej tej wartości. Pieniądze będą wprowadzane do obiegu stopniowo i równomiernie przez wiele lat przez węzły tworzące sieć, proporcjonalnie do wniesionego czasu pracy CPU.

By program mógł odbierać połączenia musisz odblokować port 8333 TCP na twoim firewallu/ routerze. To znacznie zwiększy liczbę węzłów z którymi będziesz się mógł połączyć.

Bitcoin może używać sieci TOR. Opcja ta dostępna jest z linii komend:
bitcoin -proxy=127.0.0.1:9050

Jeżeli chcesz pozostać anonimowy, nie wyjawiaj żadnych informacji łączących twój adres konta bitcoin z twoimi danymi osobowymi. Zamiast tego powinieneś użyć nowego adresu konta dla każdej płatności (tranzakcji) którą otrzymujesz.
</source>

==Dutch==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin P2P Cryptovaluta</h2>
<p>Bitcoin is een op peer-to-peer gebaseerde, digitale valuta. Peer-to-peer (P2P) houdt in dat er geen centraal gezag is dat nieuw geld kan uitgeven of de transacties kan volgen. Integendeel, deze taken worden collectief beheerd door de knooppunten in het netwerk. Voordelen:</p>
<ul>
<li>Boek gemakkelijk geld over via het Internet, zonder te hoeven vertrouwen op derden.</li>
<li>Derden kunnen jouw transacties niet tegenhouden of controleren.</li>
<li><strong>Bitcointransacties zijn vrijwel gratis</strong>, daar waar credit cards en online betaalsystemen normaal gesproken 1-5% kosten per transactie in rekening brengen plus verschillende andere toeslagen die kunnen oplopen tot honderden euro's.</li>
<li>Wees beschermd tegen de instabiliteit die veroorzaakt wordt door "fractional-reserve banking" en slecht beleid van centrale banken. De inflatie van de geldvoorraad van het Bitcoinsysteem is gelimiteerd en gelijk verdeeld (CPU kracht) over het gehele netwerk en niet gemonopoliseerd door banken.</li>
</ul>
<p>Bitcoin is een open source project gecreeërd door Satoshi Nakamoto en is op dit moment in een bèta ontwikkelfase. Haal de nieuwste versie van Bitcoin vanaf de <a href="http://sourceforge.net/projects/bitcoin/">SourceForge projectpagina</a>.</p>
<p>Schermafdrukken:</p>
<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a></p>
<p>Bitcoin gebruiken:</p>
<p>Zet de optie aan in het menu Options -> Generate Coins om een aantal coins te krijgen voor het helpen om het netwerk te laten draaien. Bitcoin draait op de achtergrond als je computer niets doet is en het zou je computer niet moeten vertragen. Het kan soms dagen duren voordat je succesvol een Bitcoin gegenereerd hebt, dus wees geduldig. De tijd varieërt and hangt af van de hoeveelheid CPU tijd je bijdraagt.</p>
<p>In totaal zullen er 21.000.000 Bitcoins in circulatie komen. Er zullen nooit meer Bitcoins komen. De Bitcoins komen geleidelijk in circulatie, gestaag gedurende meerdere jaren en via de knooppunten in het network in verhouding tot de CPU tijd die zij bijdragen.</p>
<p>Om binnenkomende connecties te kunnen ontvangen, moet je de firewall instellen zodat poort 8333 (TCP) doorgestuurd wordt naar je computer. Hierdoor kan je met meer knooppunten verbinding maken.</p>
</source>

==Esperanto==
<source lang="html4strict">
<h2 class="homepage-title page-title">Bitcoin P2P Cxifromono</h2>
<p>Bitcoin estas mono bazita sur reto de samtavola ŝutado. Samtavola ŝutado signifas ke estas nenia centra aŭtoritato por doni novajn monerojn aŭ kontroli transdonojn. Anstataŭe, tiuj taskoj estas manipulataj de la nodoj de la reto. Avantaĝoj:</p>
<ul>
<li>Transdoni monon facile tra la Interreto, sen devo fidi je mezulo.</li>
<li>Triaj partioj ne povas antaŭmalhelpi aŭ regi viajn transdonojn.</li>
<li><strong>Transdonoj per Bitcoin estas efektive senpagaj</strong>, dum kreditkartoj kaj surretaj pagosistemoj tipe postulas po 1-5% por unu transdono kaj variajn aliajn kostojn ĝis centoj da dolaroj.</li>

<li>Estu sekura, for de la malstabileco de frakcia konservo-bankado kaj malbonaj politikoj de centraj bankoj. La limigita inflacio de la provizo de mono en la sistemo de Bitcoin estas ebene distribuata (laŭ la potenco de procesoroj) tra la reto, kaj ne monopoliigita de la bankoj.</li>
</ul>
<p>La projekto de Bitcoin havas malfermitan kodon kaj estas kreita de Satoshi Nakamoto. Ĝi nuntempe estas en beta stato. La kodo de Bitcoin estas gastigita ĉe <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.</p>
<p>Ekrankopioj:</p>
<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Bildo de la ĉeffenestro" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Bildo de la transdonilo" /></a></p>
<p>Kiel uzi Bitcoin:</p>
<p>Ŝaltu Options->Generate Coins (Opcioj->Generu Monerojn) por ricevi kelkajn monerojn pro via helpado funkciigi la reton. La softvaro de Bitcoin funkcias en la fono dum via komputilo nenion faras kaj devus ne malrapidigi aliajn softvarojn. Vi eble bezonos kelkajn tagojn generi moneron, do estu pacienca. La tempo bezonata varias kaj dependas de kiom da tempo vi kontribuas funkciigante la reton. </p>
<p>La tuta iama cirkulado de moneroj estos 21 milionoj. Neniam estos pli da moneroj ol tio. La moneroj malrapide eniras la cirkuladon, je ebena rapideco, dum multaj jaroj, al nodoj kiuj subtenas la reton laŭ la proporcio de tempo iliaj procesoroj kontribuas.</p>

<p>Por ricevi envenajn konektojn, vi devas agordi vian fajroŝirmilon por plusendi pordon 8333 (TCP) al via komputilo. Tio pliigos la nombron da nodoj kun kiuj vi povos konekti.</p>
<p>Bitcoin povas esti uzata per Tor per la komandlineo:<br />
bitcoin -proxy=127.0.0.1:9050</p>
<p>Se vi penas resti anonima (pseŭdanonima, verdire), estu zorga ne malkaŝi ian informon kiu ligas vin kun viaj adresoj de Bitcoin. Vi devus uzi novan adreson de Bitcoin por ĉiu nova pago kiun vi ricevas.</p>
</source>

==Hebrew==
Please note that Hebrew is written right-to-left and this should be expressed somewhere in the HTML/CSS.

<source lang="html4strict"><i>אם ברשותכם גרסה 0.3.9 ומטה, אנא שדרגו בכדי לקבל עדכון אבטחה חשוב!</i>

<h2 class="homepage-title page-title">מטביט, המטבע הוירטואלי - Bitcoin P2P Virtual Currency</h2>

מטביט הוא מטבע דיגיטלי ברשת P2P. פרוטוקול ה-P2P (peer-to-peer) אומר שאין רשות מרכזית שמנפיקה כסף נוסף או עוקבת אחר עסקאות. במקום זאת, פעילויות אלה מנוהלות באופן קולקטיבי על ידי השותפים ברשת. יתרונות:

<ul>
<li>ניתן לשלוח מטביטים בקלות באמצעות האינטרנט, מבלי צורך להסתמך על מתווכים.</li>
<li>עסקאות אינן הפיכות כעיקרון בסיסי.</li>
<li>ניתן להיות בטוחים מחוסר יציבות הנגרמת על ידי בנקים המשתמשים ביחסי רזרבה ועל ידי בנקים מרכזיים. האינפלציה המוגבלת של המטביט מחולקת באופן שווה (לפי כוח מיחשוב) בקרב כל הרשת, ללא מונופול בנקאי.</li>
</ul>

מטביט (Bitcoin) הוא פרויקט קוד פתוח שנמצא כעת בשלב הבטא. הפרויקט מתארח ב<a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.

צילומי מסך:

<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="צילום המסך הראשי" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="מסך משלוח" /></a></p>

שימוש במטביט:

במשך השעה-שעתיים הראשונות, מספר הבלוקים יגדל במהירות, בזמן ששרשרת הבלוקים תתקבל.

הפעל את אפשרויות -> יצירת מטבעות כדי לתרום את זמן המעבד הבטל שלך לרשת. תוכנת המטביט פועלת ברקע כאשר המחשב אינו פעיל ולא אמורה להאט תוכניות אחרות.

בסופו של דבר, יהיו סך הכל 21 מליון מטביטים. לעולם לא יהיו יותר מטביטים מכך. המטבעות נכנסים לשוק לאט, בקצב סדיר לאורך שנים רבות, לחשבונם של אנשים המשתמשים בתוכנה ביחסיות לכמות זמן המעבר שהם תורמים. עם כוח המיחשוב הנוכחי ברשת, רוב המעבדים יעבדו חודשים לפני שיסיימו לייצר 50 מטביטים.

ניתן לקבל מטביטים בחינם מ<a href="http://freebitcoins.appspot.com/">ברז המטביט</a>. אם תוכנת המטביט רצה בזמן שתתקבל העסקה, תוכלו לראותה מיד, אחרת עלולות לעבור לפחות 10 דקות לאחר שנשלחה ועל כל הבלוקים לסיים לרדת לפני כן. נכון לדצמבר 2010, ישנם 97000 בלוקים.

בכדי לקבל חיבורים נכנסים, סדר זאת כך שקיר האש (firewall) מקדם את פורט 8333 (TCP) למחשב. דבר זה מגדיל את מספר האנשים אליהם תוכל להתחבר.
</source>

==Brazilian Portuguese==
<source lang="html4strict">
<i>Se você possui a versão 0.3.9 ou inferior, por favor atualize para uma importante atualização de segurança</i>

<h2 class="homepage-title page-title"> Bitcoin, a Moeda Virtual P2P</h2>

Bitcoin é uma moeda digital peer-to-peer. Peer-to-peer(P2P) significa que não há uma autoridade central para emitir novas cédulas ou manter o controle sob operações financeiras. Em vez disso,essas tarefas são feitas coletivamente por nodes("nós") da network. Vantagens:

<ul>
<li> Bitcoins são enviadas facilmente através da Internet, sem a necessidade de intermediários.</li>
<li> Transações são projetadas para serem irreversíveis</li>
<li> Fique seguro da instabilidade da reserva fracionária e dos bancos centrais. A inflação limitada causada pela oferta do sistema de moeda Bitcoin é distribuída igualmente (pelo poder do CPU) para toda a rede, não monopolizada por bancos.</li>
</ul>

Bitcoin é um projeto open-source atualmente na fase beta de desenvolvimento. O desenvolvimento é hosteado no link <a href="http://sourceforge.net/projects/bitcoin/">SourceForge</a>.

Screenshots:

<p><a href="/sites/default/files/screen3.png"><img src="/sites/default/files/screen3_thumb.png" alt="Main window screenshot" /></a></p>
<p><a href="/sites/default/files/screen4.png"><img src="/sites/default/files/screen4_thumb.png" alt="Sending dialog screenshot" /></a></p>

Usando o Bitcoin:

Durante as duas primeiras horas, a contagem de blocos vai aumentar rapidamente, pois a corrente de blocos está sendo recebida.

Deixe ligado Options->Generate Coins para contribuir para a rede com o tempo inativo de seu CPU. Bitcoin funciona no background quando seu computador está inativo e não deve deixar outros programas mais lentos.

O total de circulação será de 21 milhões de Bitcoins. Jamais haverá mais moedas que isso. As moedas estão entrando em circulação de forma gradual, em um ritmo constante de vários anos, para nodes(nós) que apoiam a rede em proporção ao tempo de CPU que eles contribuam. Com o atual poder de CPU na rede, a maioria dos CPUs demorará meses para gerar 50 BTC.

Você pode conseguir alguns Bitcoins de graça no link <a href="http://freebitcoins.appspot.com/">Bitcoin Faucet</a>. Se o Bitcoin estiver funcionando quando você receber uma transação, você consegue ve-lâ imediatamente. Caso contrário, pode demorar 10 minutos ou mais depois que foi enviada e todos os blocos devem terminar o download. A partir de Dezembro de 2010, há 97000 blocos.

Para receber conexões, coloque seu firewall para abrir a porta 8333 (TCP) no seu computador. Isso aumenta o número de nodes(nós) com os quais você consegue se conectar.
</source>

Digital currency

2011-03-01T11:40:55Z

Sahtor: fix typo

A '''digital currency''', (also known as cryptcurrency, cyber currency, digital cash, digital currency, digital money, e-currency, e-money, electronic cash, electronic currency, electronic money) refers to money or scrip which is only exchanged electronically.

When money transfers occur as a bank wire transfer or ACH payment, or even transfers of money using services such as [[PayPal]], the funds are sent electronically but the currency transmitted is representative money and what transfers is an underlying fiat currency.

==See Also==
* List of [[:Category:Digital currencies|Digital currencies]]
* [[:Category:Money transmitters|Money transmitters]]

==External Links==
* [http://en.wikipedia.org/wiki/Electronic_money Electronic Money] article on Wikipedia

Original Bitcoin client/API calls list

2011-03-01T11:29:38Z

Sahtor: fix typo

Bitcoin API call list (as of version 0.3.19)

== Common operations ==

=== Listing my bitcoin addresses ===

Listing the bitcoin addresses in your wallet is easily done via ''listreceivedbyaddress''. It normally lists only addresses which already have received transactions, however you can list all the addresses by setting the first argument to 0, and the second one to true

== Full list ==

Required arguments are denoted inside < and > Optional arguments are inside [ and ].

{|class="wikitable"
! Command !! Parameters !! Description
|-
| backupwallet || <destination> || Safely copies wallet.dat to destination, which can be a directory or a path with filename.
|-
| getaccount || <bitcoinaddress> || Returns the account associated with the given address.
|-
| getaccountaddress || <account> || Returns the current bitcoin address for receiving payments to this account.
|-
| getaddressesbyaccount || <account> || Returns the list of addresses for the given account.
|-
| getbalance || [account] [minconf=1] || If [account] is not specified, returns the server's total available balance.<br/>If [account] is specified, returns the balance in the account.
|-
| getblockbycount || height || Dumps the block existing at specified height. '''Note: this is not available in the official release'''
|-
| getblockcount || || Returns the number of blocks in the longest block chain.
|-
| getblocknumber || || Returns the block number of the latest block in the longest block chain.
|-
| getconnectioncount || || Returns the number of connections to other nodes.
|-
| getdifficulty || || Returns the proof-of-work difficulty as a multiple of the minimum difficulty.
|-
| getgenerate || || Returns true or false whether bitcoind is currently generating hashes
|-
| gethashespersec || || Returns a recent hashes per second performance measurement while generating.
|-
| getinfo || || Returns an object containing various state info.
|-
| getnewaddress || [account] || Returns a new bitcoin address for receiving payments. If [account] is specified (recommended), it is added to the address book so payments received with the address will be credited to [account].
|-
| getreceivedbyaccount || <account> [minconf=1] [includeempty=false] || Returns the total amount received by addresses with <account> in transactions with at least [minconf] confirmations.
|-
| getreceivedbyaddress || <bitcoinaddress> [minconf=1] [includeempty=false] || Returns the total amount received by <bitcoinaddress> in transactions with at least [minconf] confirmations.
|-
| gettransaction || <txid> || Get detailed information about <txid>
|-
| getwork || [data] || If [data] is not specified, returns formatted hash data to work on:
* "midstate" : precomputed hash state after hashing the first half of the data
* "data" : block data
* "hash1" : formatted hash buffer for second hash
* "target" : little endian hash target
If [data] is specified, tries to solve the block and returns true if it was successful.
|-
| help || [command] || List commands, or get help for a command.
|-
| listreceivedbyaccount || [minconf=1] [includeempty=false] || Returns an array of objects containing:
* "account" : the account of the receiving addresses
* "amount" : total amount received by addresses with this account
* "confirmations" : number of confirmations of the most recent transaction included
|-
| listreceivedbyaddress || [minconf=1] [includeempty=false] || Returns an array of objects containing:
* "address" : receiving address
* "account" : the account of the receiving address
* "amount" : total amount received by the address
* "confirmations" : number of confirmations of the most recent transaction included
|-
| listtransactions || <account> [count=10] || Returns up to [count] most recent transactions for account <account>.
|-
| move || <fromaccount> <toaccount> <amount> [minconf=1] [comment] || Move from one account in your wallet to another.
|-
| sendfrom || <fromaccount> <tobitcoinaddress> <amount> [minconf=1] [comment] [comment-to] || <amount> is a real and is rounded to the nearest 0.01
|-
| sendtoaddress || <bitcoinaddress> <amount> [comment] [comment-to] || <amount> is a real and is rounded to the nearest 0.01
|-
| setaccount || <bitcoinaddress> <account> || Sets the account associated with the given address.
|-
| setgenerate || <generate> [genproclimit] || <generate> is true or false to turn generation on or off.<br/>Generation is limited to [genproclimit] processors, -1 is unlimited.
|-
| stop || || Stop bitcoin server.
|-
| validateaddress || <bitcoinaddress> || Return information about <bitcoinaddress>.
|}

==See Also==

* [[Original Bitcoin client]]

[[Category:Technical]]
[[Category:Developer]]

Securing your wallet

2011-03-01T11:24:00Z

Sahtor: fix typo

==Introduction==

Wallet security can be broken down into two independent goals:
# Protecting your wallet against loss.
# Protecting your wallet against theft.

In the case that your current wallet hasn't been protected adequately (e.g. put online with a weaker password):
# Making a new secure wallet, using appropriate long-term protection.

==Technical Background==

Bitcoin transactions send Bitcoins to a specific public key. A Bitcoin address is an encoded hash of a public key. In order to use received Bitcoins, you need to have the private key matching the public key you received with. This is sort of like a super long password associated with an account (public key). Your Bitcoin wallet contains all of the private keys necessary for spending your received transactions. If you delete your wallet without a backup, then you no longer have the authorization information necessary to claim your coins, and the coins associated with those keys are lost forever.

The wallet contains a pool of queued keys. By default there are 100 keys in the keypool. The size of the pool is configurable using the undocumented "--keypool" command line argument. When you need an address for whatever reason (send, “new address”, generation, etc.), the key is not actually generated freshly, but taken from this pool. A brand new address is generated to fill the pool back to 100. So when a backup is first created, it has all of your old keys plus 100 unused keys. After sending a transaction, it has 99 unused keys. After a total of 100 new-key actions, you will start using keys that are not in your backup. Since the backup does not have the private keys necessary for authorizing spends of these coins, restoring from the old backup will cause you to lose Bitcoins.

Creating a new address generates a new pair of public and private keys, which are added to your wallet. Each keypair is mostly random numbers, so they cannot be known prior to generation. If you backup your wallet and then create more than 100 new addresses, the keypair associated with the newest addresses will not be in the old wallet because the new keypairs are only known after creating them. Any coins received at these addresses will be lost if you restore from the backup.

The situation is made somewhat more confusing because the receiving addresses shown in the UI are not the only keys in your wallet. Each Bitcoin generation is given a new public key, and, more importantly, each sent transaction also sends some number of Bitcoins back to yourself at a new key. When sending Bitcoins to anyone, you generate a new keypair for yourself and simultaneously send Bitcoins to your new public key and the actual recipient's public key. This is an anonymity feature – it makes tracking Bitcoin transactions much more difficult.

So if you create a backup, do more than 100 things that cause a new key to be used, and then restore from the backup, some Bitcoins will be lost. Bitcoin has not deleted any keys (keys are never deleted) – it has created a new key that is not in your old backup and then sent Bitcoins to it.

== Making a new wallet ==

In the case that a wallet has been distributed, or stored, in a (real or potential) compromised state, it is wise to create a new wallet and transfer the full balance of Bitcoins to an address contained only in the newly created wallet.

For example, this will be necessary if one created a wallet with a password of 12 characters, as suggested. However a few years have passed and the wallet is now more easily compromised. Just re-encrypting isn't secure. One needs to make a new wallet and make the old wallet worthless (spending the funds to the new wallet).

==Making a secure workspace==

===Linux===

The first step is to make a [http://www.howtogeek.com/howto/ubuntu/add-a-user-on-ubuntu-server/ new user,] so type:

sudo adduser new_user_name

when you get to the prompt 'Enter the new value, or press ENTER for the default', just keep hitting ENTER.

Then switch user to the new user. To get to the new user you can use the switch user icon for your system, which on Ubuntu is in the 'System/Quit' screen, or if there is no switch icon on your system you can log out and log back in as the new user. Then click on a folder in the new user to display the file browser, then keep going up folders until you see the new user home directory, then right click to bring up the Properties dialog, then click on the Permissions tab, then in the Others section, set the folder access to None.

For secure browsing, open Firefox, and then go into the Edit menu and click Preferences. Starting from the left, click on the General tab, and in the 'Startup/When Firefox starts' pop up menu, choose 'Show a Blank Page'. Then click on the Content tab, and deselect 'Load images automatically' and deselect 'Enable Javascript'. Then click on the Privacy tab, and in the 'History/Firefox will' pop up menu, choose 'Never remember history'. Then click on the Security tab, and in the Passwords section, deselect 'Remember passwords for sites' and deselect 'Use a master password'. Then click on the Advanced tab, then click on the Update tab, and then in the 'Automatically check for updates to' section, deselect 'Add-ons' and 'Search Engines'.

When javascript is disabled, the [http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.3.19/bitcoin-0.3.19-linux.tar.gz/download linux download page] will not download automatically, so you'll have to click on the 'direct link' part of the "Problems with the download? Please use this 'direct link' or try another mirror." line.

After you've made your secure new user, to maintain security you should use it only for bitcoin.

== Locating BitCoin's data directory ==

=== Windows ===

Go to Start -> Run (or press WinKey+R) and run this:

explorer %APPDATA%\BitCoin

BitCoin's data folder will open. For most users, this is the following locations:

C:\Documents and Settings\YourUserName\Application data\BitCoin (XP)

C:\Users\YourUserName\Appdata\Roaming\BitCoin (Vista and 7)

"AppData" and "Application data" are hidden by default.

=== Linux ===

By default BitCoin will put its data here:

~/.bitcoin/

You need to do a "ls -a" to see directories that start with a dot.

If that's not it, you can do a search like this:

find / -name wallet.dat -print 2>/dev/null

=== Mac ===

By default BitCoin will put its data here:

~/Library/Application Support/Bitcoin/

==Backup==

The only file you need to back up is "wallet.dat". Ensure that BitCoin is closed, copy this file somewhere else, encrypt it, and put it somewhere safe. Ideally, you would put this file in two places: one nearby, and one 100+ miles away.

You can use the [[api|backupwallet]] JSON-RPC command to back up without shutting down Bitcoin.

=== General Solutions ===

Your wallet.dat file is not encrypted by BitCoin. Anyone who can access it can easily steal all of your coins. Use one of these encryption programs if there is any chance someone might stumble upon your wallet.
* [http://www.7-zip.org/ 7-zip] - Supports strongly-encrypted archives.
* [http://www.axantum.com/axcrypt/ AxCrypt]
* [http://www.truecrypt.org/ TrueCrypt] - Volume-based on-the-fly encryption (for advanced users)
* [http://www.rarlab.com/ WinRar] - Commonly used archive software that supports verification records and encryption.

There is also a list of [[OpenSourceEncryptionSoftware|open source encryption software.]]

==== Password Strength ====
Brute-force password cracking has come a long distance, a previously thought secure password of random [a-Z] [0-9] [!-~] of 8 characters long can be trivially solved now (using appropriate hardware)... The recommended length is '''at least''' 12 characters long.

If you use keyfiles in addition to a password, it is unlikely that your encrypted file can ever be cracked using brute force methods, even 10 years from now when even a 12 character password might be too short.

Assume that any encrypted files you store online (eg. gmail, Dropbox) will be stored somewhere forever and can never be erased.

==== Storage of Archive ====
One of the most simple places to store a appropriately encrypted archive of your wallet.dat file is to email yourself the archive. Services like gmail.com use very comprehensive distributed networks that make the loss of data very unlikely. One can even encrypt the name of the files within the archive, and name the archive something less inviting, such as: 'personal notes' or 'car insurance'.

Another solution is to use a file storage service like [http://www.dropbox.com Dropbox] and [http://en.wikipedia.org/wiki/Comparison_of_online_backup_services others], including the more secure [http://www.spideroak.com SpiderOak].

=== Linux solution ===

Linux users can setup cron by running 'crontab -e' and adding this line:

01 */1 * * * /usr/local/bin/backupwallet.sh

This cron line runs backupwallet.sh at the 01 minute of every hour. Remember to add a newline after the last line of the crontab file, or else the last line won't run.

backupwallet.sh:

#!/bin/bash

TS=$(date "+%Y%m%d-%H-%M")
WALLET=/tmp/wallet${TS}
WALLET_E=/tmp/wallet${TS}.crypt

if
echo -n making backup...
bitcoind backupwallet $WALLET
[[ ! -s "$WALLET" ]]
then echo failed
elif
echo done
echo -n encrypting....
! gpg -r myusername --output $WALLET_E --encrypt $WALLET
then echo failed
elif
echo done
echo -n copying to distant server...
! scp $WALLET_E user@myserver.org:~/wallets/
then echo failed
else echo done
fi

rm -f $WALLET $WALLET_E

The shell script:

* Calls bitcoind backupwallet to create a time/date-stamped wallet.
* GPG encrypts the wallet with your public key.
* Copies the result to a backup location.

[[Category:Technical]]

==Restore==

Assuming your backup is recent enough that you haven't used up all of your keypool... restoring a wallet to a new (or old) location and rescanning the block chain should leave you with all your coins. Just follow these steps:
* Quit bitcoin(d).
* Copy your backed up wallet.dat into your bitcoin profile directory.
* If copying into existing profile, delete file ''blkindex.dat'', to make the client rescan the block chain.
And you'll be good as new.

==Erasing Plain Text Wallets==

A good practice is to keep at least two wallets, one as a "current account" for everyday transactions and one as a "savings account" where you store the majority of your Bitcoins.

The "savings account" wallet should be backed up in encrypted form only and all plaintext copies of this wallet should be erased. In case someone gains unauthorised access to your computer (either by physically stealing it or by exploiting a system vulnerability via the internet), they will only be able to spend the coins in your "current account" wallet.

In most operating systems, including Windows, Linux, and Mac OS X, simply deleting a wallet.dat file will ''not'' generally destroy it. It is likely that advanced tools can still be used to recover the wallet.dat file, even after it has been deleted.

The Linux '''shred''' command can be used to overwrite the wallet file with random data prior to deleting; this particular copy of the file will then be practically impossible to recover. Using shred (and similar tools on Windows) however does not guarantee that still other copies don't exist somewhere hidden on your HD. That will depend on your system configuration and what packages you have installed. Some system restore and backup tools, for instance, create periodic snapshots of your filesystem, duplicating your wallet.dat.

For Windows, the built-in command ''cipher /w'' will shred all previously-deleted files. [http://www.cylog.org/utilities/cybershredder.jsp CyberShredder] can securely deleted individual files.

==eWallet==

Storing bitcoins with an [[eWallet]] provider incurs risks as well.

==See Also==

* [[Data directory]]

Protocol documentation

2011-03-01T11:06:13Z

Sahtor: fix 2 typos

Sources:
* [[Original Bitcoin client]] source
* [http://www.bitcoin.org/wiki/doku.php?id=bitcoins_draft_spec_0_0_1 Draft spec on bitcoin wiki]

Type names used in this documentation are from the C99 standard.

== Common standards ==

=== Hashes ===

Usually, when a hash is computed within bitcoin, it is computed twice. Most of the time [http://en.wikipedia.org/wiki/SHA-2 SHA-256] hashes are used, however [http://en.wikipedia.org/wiki/RIPEMD RIPEMD-160] is also used when a shorter hash is desirable (for example when creating a bitcoin address).

Example of double-SHA-256 encoding of string "hello":

hello
2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824 (first round of sha-256)
9595c9df90075148eb06860365df33584b75bff782a510c6cd4883a419833d50 (second round of sha-256)

For bitcoin addresses (RIPEMD-160) this would give:

hello
2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824 (first round is sha-256)
b6a9c8c230722b7c748331a8b450f05566dc7d0f (with ripemd-160)

=== Signatures ===

Bitcoin uses [http://en.wikipedia.org/wiki/Elliptic_curve_cryptography Elliptic Curve] [http://en.wikipedia.org/wiki/Digital_Signature_Algorithm Digital Signature Algorithm] (ECDSA) to sign transactions.

For ECDSA the secp256k1 curve from http://www.secg.org/collateral/sec2_final.pdf is used.
Public keys (in scripts) are given as 04 <x> <y> where x and y are 32 byte strings representing the coordinates of a point on the curve.

=== Transaction Verification ===
{{See also|OP_CHECKSIG}}

The first transaction of a block is usually the generating transaction, which do not include any "in" transaction, and generate bitcoins (from fees for example) usually received by whoever solved the block containing this transaction.
Such transactions are called a "coinbase transaction" and are accepted by bitcoin clients without any need to execute scripts, provided there is only one per block.

If a transaction is not a coinbase, it references previous transaction hashes as input, and the index of the other transaction's output used as input for this transaction.
The script from the in part of this transaction is executed.
Then the script from the out part of the referenced transaction is executed.
It is considered valid if the top element of the stack is true.

=== Addresses ===

A bitcoin address is in fact the hash of a ECDSA public key, computed this way:

Version = 1 byte of 0 (zero); on the test network, this is 1 byte of 111
Key hash = Version concatenated with RIPEMD-160(SHA-256(public key))
Checksum = 1st 4 bytes of SHA-256(SHA-256(Key hash))
Bitcoin Address = Base58Encode(Key hash concatenated with Checksum)

The Base58 encoding used is home made, and has some differences. Especially, leading zeroes are kept as single zeroes when conversion happens.

== Common structures ==

Almost all integers are encoded in little endian. Only IP or port number are encoded big endian.

=== Message structure ===

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 4 || magic || uint32_t || Magic value indicating message origin network, and used to seek to next message when stream state is unknown
|-
| 12 || command || char[12] || ASCII string identifying the packet content, NULL padded (non-NULL padding results in packet rejected)
|-
| 4 || length || uint32_t || Length of payload
|-
| 4 || checksum || uint32_t || First 4 bytes of sha256(sha256(payload)) (not included in version or verack)
|-
| ? || payload || char[] || The actual data
|}

Known magic values:

{|class="wikitable"
! Network !! Magic value
|-
| main || F9BEB4D9
|-
| testnet || FABFB5DA
|}

=== Variable length integer ===

Integer can be encoded depending on the represented value to save space. Variable length integers always precede an array/vector of a type of data that may vary in length.

{|class="wikitable"
! Value !! Storage length !! Format
|-
| < 0xfd || 1 || uint8_t
|-
| <= 0xffff || 3 || 0xfd + uint16_t
|-
| <= 0xffffffff || 5 || 0xfe + uint32_t
|-
| - || 9 || 0xff + uint64_t
|}

=== Variable length string ===

Variable length string can be stored using a variable length integer followed by the string itself.

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| ? || length || var_int || Length of the string
|-
| ? || string || char[] || The string itself (can be empty)
|}

=== Network address ===

When a network address is needed somewhere, this structure is used. This protocol and structure supports IPv6, '''but note that the official client currently only supports IPv4 networking'''.

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 8 || services || uint64_t || same service(s) listed in [[#version|version]]?
|-
| 16 || IPv6/4 || char[16] || IPv6 address. Network byte order. The official client only supports IPv4 and only reads the last 4 bytes to get the IPv4 address. However, the official client writes the IPv4 address into the message as a 16 byte [http://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresses IPv4-mapped IPv6 address]
(12 bytes ''00 00 00 00 00 00 00 00 00 00 FF FF'', followed by the 4 bytes of the IPv4 address).
|-
| 2 || port || uint16_t || port number, network byte order
|}

Hexdump example of Network address structure

<pre>
0000 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0010 00 00 FF FF 0A 00 00 01 20 8D ........ .

Network address:
01 00 00 00 00 00 00 00 - 1 (NODE_NETWORK? see services listed under version command)
00 00 00 00 00 00 00 00 00 00 FF FF 0A 00 00 01 - IPv6: ::ffff:10.0.0.1 or IPv4: 10.0.0.1
20 8D - Port 8333
</pre>

=== Inventory Vectors ===

Inventory vectors are used for notifying other nodes about objects they have or data which is being requested.

Inventory vectors consist of the following data format:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 4 || type || uint32_t || Identifies the object type linked to this inventory
|-
| 32 || hash || char[32] || Hash of the object
|}

The object type is currently defined as one of the following possibilities:

{|class="wikitable"
! Value !! Name !! Description
|-
| 0 || ERROR || Any data of with this number may be ignored
|-
| 1 || MSG_TX || Hash is related to a transaction
|-
| 2 || MSG_BLOCK || Hash is related to a data block
|}

Other Data Type values are considered reserved for future implementations.

=== Block Headers ===

Block headers are sent in a headers packet in response to a getheaders message.

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 4 || version || uint32_t || Block version information, based upon the software version creating this block
|-
| 32 || prev_block || char[32] || The hash value of the previous block this particular block references
|-
| 32 || merkle_root || char[32] || The reference to a Merkle tree collection which is a hash of all transactions related to this block
|-
| 4 || timestamp || uint32_t || A timestamp recording when this block was created (Limited to 2106!)
|-
| 4 || bits || uint32_t || The calculated difficulty target being used for this block
|-
| 4 || nonce || uint32_t || The nonce used to generate this block… to allow variations of the header and compute different hashes
|-
| 1 || txn_count || uint8_t || Number of transaction entries, this value is always 0
|}

== Message types ==

=== version ===

When a node receives an incoming connection, it will immediately advertise its version. No futher communication is possible until both peers have exchanged their version.

Payload:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 4 || version || uint32_t || Identifies protocol version being used by the node
|-
| 8 || services || uint64_t || bitfield of features to be enabled for this connection
|-
| 8 || timestamp || uint64_t || standard UNIX timestamp in seconds
|-
| 26 || addr_me || net_addr || The network address of the node emitting this message
|-
|colspan="4"| version >= 106
|-
| 26 || addr_you || net_addr || The network address seen by the node emitting this message (ie, the address of the receiving node)
|-
| 8 || nonce || uint64_t || Node random unique id. This id is used to detect connections to self
|-
| ? || sub_version_num || var_str || Secondary Version information (null terminated?)
|-
|colspan="4"| version >= 209
|-
| 4 || start_height || uint32_t || The last block received by the emitting node
|}

If the emitter of the packet has version >= 209, a "verack" packet shall be sent if the version packet was accepted.

The following services are currently assigned:

{|class="wikitable"
! Value !! Name !! Description
|-
| 1 || NODE_NETWORK || This node can be asked for full blocks instead of just headers.
|}

Hexdump example of version message (note the message header for this version message does not have a checksum):
<pre>
0000 F9 BE B4 D9 76 65 72 73 69 6F 6E 00 00 00 00 00 ....version.....
0010 55 00 00 00 9C 7C 00 00 01 00 00 00 00 00 00 00 U....|..........
0020 E6 15 10 4D 00 00 00 00 01 00 00 00 00 00 00 00 ...M............
0030 00 00 00 00 00 00 00 00 00 00 FF FF 0A 00 00 01 ................
0040 DA F6 01 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0050 00 00 00 00 FF FF 0A 00 00 02 20 8D DD 9D 20 2C .......... ... ,
0060 3A B4 57 13 00 55 81 01 00 :.W..U...

Message header:
F9 BE B4 D9 - Main network magic bytes
76 65 72 73 69 6F 6E 00 00 00 00 00 - "version" command
55 00 00 00 - Payload is 85 bytes long
- No checksum in version message
Version message:
9C 7C 00 00 - 31900 (version 0.3.19)
01 00 00 00 00 00 00 00 - 1 (NODE_NETWORK services)
E6 15 10 4D 00 00 00 00 - Mon Dec 20 21:50:14 EST 2010
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF FF 0A 00 00 01 DA F6 - Sender address info - see Network Address
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF FF 0A 00 00 02 20 8D - Recipient address info - see Network Address
DD 9D 20 2C 3A B4 57 13 - Node random unique ID
00 - "" sub-version string (string is 0 bytes long)
55 81 01 00 - Last block sending node has is block #98645
</pre>

=== verack ===

The ''verack'' message is sent in reply to ''version'' for clients >= 209. This message consists of only a [[#Message structure|message header]] with the command string "verack".

Hexdump of the verack message:

<pre>
0000 F9 BE B4 D9 76 65 72 61 63 6B 00 00 00 00 00 00 ....verack......
0010 00 00 00 00 ....

Message header:
F9 BE B4 D9 - Main network magic bytes
76 65 72 61 63 6B 00 00 00 00 00 00 - "verack" command
00 00 00 00 - Payload is 0 bytes long
</pre>

=== addr ===

Provide information on known nodes of the network. Non-advertised nodes should be forgotten after typically 3 hours

Payload (maximum payload length: 1000 bytes):

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 1+ || count || var_int || Number of address entries
|-
| 30x? || addr_list || (uint32_t + net_addr)[] || Address of other nodes on the network. version < 209 will only read the first one
|}

'''Note''': Starting version 31402, addresses are prefixed with a timestamp. If no timestamp is present, the addresses should not be relayed to other peers, unless it is indeed confirmed they are up.

Hexdump example of ''addr'' message:
<pre>
0000 F9 BE B4 D9 61 64 64 72 00 00 00 00 00 00 00 00 ....addr........
0010 1F 00 00 00 7F 85 39 C2 01 E2 15 10 4D 01 00 00 ......9.....M...
0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF ................
0030 FF 0A 00 00 01 20 8D .D(.. .

Message Header:
F9 BE B4 D9 - Main network magic bytes
61 64 64 72 00 00 00 00 00 00 00 00 - "addr"
1F 00 00 00 - payload is 31 bytes long
7F 85 39 C2 - checksum of payload

Payload:
01 - 1 address in this message

Address:
E2 15 10 4D - Mon Dec 20 21:50:10 EST 2010 (only when version is >= 31402)
01 00 00 00 00 00 00 00 - 1 (NODE_NETWORK service - see version message)
00 00 00 00 00 00 00 00 00 00 FF FF 0A 00 00 01 - IPv4: 10.0.0.1, IPv6: ::ffff:10.0.0.1 (IPv4-mapped IPv6 address)
20 8D - port 8333
</pre>

=== inv ===

Allows a node to advertise its knowledge of one or more objects. It can be received unsolicited, or in reply to ''getblocks''.

Payload (maximum payload length: 50000 bytes):

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| ? || count || var_int || Number of inventory entries
|-
| 36x? || inventory || inv_vect[] || Inventory vectors
|}

=== getdata ===

getdata is used in response to inv, to retrieve the content of a specific object, and is usually sent after receiving an ''inv'' packet, after filtering known elements.

Payload (maximum payload length: 50000 bytes):

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| ? || count || var_int || Number of inventory entries
|-
| 36x? || inventory || inv_vect[] || Inventory vectors
|}

=== getblocks ===

Return an ''inv'' packet containing the list of blocks starting at hash_start, up to hash_stop or 500 blocks, whichever comes first. To receive the next blocks hashes, one needs to issue getblocks again with the last known hash.

Payload:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 4 || version || uint32_t || protocol version number
|-
| 1+ || start count || var_int || number of hash_start entries
|-
| 32+ || hash_start || char[32] || hash of the last known block of the emitting node
|-
| 32 || hash_stop || char[32] || hash of the last desired block. Set to zero to get as many blocks as possible (500)
|}

=== getheaders ===

Return a ''headers'' packet containing the headers for blocks starting at hash_start, up to hash_stop or 2000 blocks, whichever comes first. To receive the next blocks hashes, one needs to issue getheaders again with the last known hash. The ''getheaders'' command is used by thin clients to quickly download the blockchain where the contents of the transactions would be irrelevant (because they are not ours).

Payload:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 4 || version || uint32_t || protocol version number
|-
| 1+ || start count || var_int || number of hash_start entries
|-
| 32+ || hash_start || char[32] || hash of the last known block of the emitting node
|-
| 32 || hash_stop || char[32] || hash of the last desired block. Set to zero to get as many blocks as possible (2000)
|}

=== tx ===

''tx'' describes a bitcoin transaction, in reply to ''getdata''

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 4 || version || uint32_t || Transaction data format version
|-
| 1+ || tx_in count || var_int || Number of Transaction inputs
|-
| 41+ || tx_in || tx_in[] || A list of 1 or more transaction inputs or sources for coins
|-
| 1+ || tx_out count || var_int || Number of Transaction outputs
|-
| 8+ || tx_out || tx_out[] || A list of 1 or more transaction outputs or destinations for coins
|-
| 4 || lock_time || uint32_t || The block number or timestamp at which this transaction is locked, or 0 if the transaction is always locked. A non-locked transaction must not be included in blocks, and it can be modified by broadcasting a new version before the time has expired (replacement is currently disabled in Bitcoin, however, so this is useless).
|}

TxIn consists of the following fields:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 36 || previous_output || outpoint || The previous output transaction reference, as an OutPoint structure
|-
| 1+ || script length || var_int || The length of the signature script
|-
| ? || signature script || char[] || Computational Script for confirming transaction authorization
|-
| 4 || sequence || uint32_t || Transaction version as defined by the sender. Intended for "replacement" of transactions when information is updated before inclusion into a block.
|}

The OutPoint structure consists of the following fields:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 32 || hash || char[32] || The hash of the referenced transaction.
|-
| 4 || index || uint32_t || The index of the specific output in the transaction. The first output is 0, etc.
|}

The Script structure consists of a series of pieces of information and operations related to the value of the transaction.

(Structure to be expanded in the future… see script.h and script.cpp for more information)

The TxOut structure consists of the following fields:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 8 || value || uint64_t || Transaction Value
|-
| 1+ || pk_script length || var_int || Length of the pk_script
|-
| ? || pk_script || char[] || Usually contains the public key as a Bitcoin script setting up conditions to claim this output.
|}

Example ''tx'' message:
<pre>
000000 F9 BE B4 D9 74 78 00 00 00 00 00 00 00 00 00 00 ....tx..........
000010 02 01 00 00 E2 93 CD BE 01 00 00 00 01 6D BD DB .............m..
000020 08 5B 1D 8A F7 51 84 F0 BC 01 FA D5 8D 12 66 E9 .[...Q........f.
000030 B6 3B 50 88 19 90 E4 B4 0D 6A EE 36 29 00 00 00 .;P......j.6)...
000040 00 8B 48 30 45 02 21 00 F3 58 1E 19 72 AE 8A C7 ..H0E.!..X..r...
000050 C7 36 7A 7A 25 3B C1 13 52 23 AD B9 A4 68 BB 3A .6zz%;..R#...h.:
000060 59 23 3F 45 BC 57 83 80 02 20 59 AF 01 CA 17 D0 Y#?E.W... Y.....
000070 0E 41 83 7A 1D 58 E9 7A A3 1B AE 58 4E DE C2 8D .A.z.X.z...XN...
000080 35 BD 96 92 36 90 91 3B AE 9A 01 41 04 9C 02 BF 5...6..;...A....
000090 C9 7E F2 36 CE 6D 8F E5 D9 40 13 C7 21 E9 15 98 .~.6.m...@..!...
0000A0 2A CD 2B 12 B6 5D 9B 7D 59 E2 0A 84 20 05 F8 FC *.+..].}Y... ...
0000B0 4E 02 53 2E 87 3D 37 B9 6F 09 D6 D4 51 1A DA 8F N.S..=7.o...Q...
0000C0 14 04 2F 46 61 4A 4C 70 C0 F1 4B EF F5 FF FF FF ../FaJLp..K.....
0000D0 FF 02 40 4B 4C 00 00 00 00 00 19 76 A9 14 1A A0 ..@KL......v....
0000E0 CD 1C BE A6 E7 45 8A 7A BA D5 12 A9 D9 EA 1A FB .....E.z........
0000F0 22 5E 88 AC 80 FA E9 C7 00 00 00 00 19 76 A9 14 "^...........v..
000100 0E AB 5B EA 43 6A 04 84 CF AB 12 48 5E FD A0 B7 ..[.Cj.....H^...
000110 8B 4E CC 52 88 AC 00 00 00 00 .N.R......

Message header:
F9 BE B4 D9 - main network magic bytes
74 78 00 00 00 00 00 00 00 00 00 00 - "tx" command
02 01 00 00 - payload is 258 bytes long
E2 93 CD BE - checksum of payload

Transaction:
01 00 00 00 - version

Inputs:
01 - number of transaction inputs

Input 1:
6D BD DB 08 5B 1D 8A F7 51 84 F0 BC 01 FA D5 8D - previous output (outpoint)
12 66 E9 B6 3B 50 88 19 90 E4 B4 0D 6A EE 36 29
00 00 00 00

8B - script is 139 bytes long

48 30 45 02 21 00 F3 58 1E 19 72 AE 8A C7 C7 36 - signature script (scriptSig)
7A 7A 25 3B C1 13 52 23 AD B9 A4 68 BB 3A 59 23
3F 45 BC 57 83 80 02 20 59 AF 01 CA 17 D0 0E 41
83 7A 1D 58 E9 7A A3 1B AE 58 4E DE C2 8D 35 BD
96 92 36 90 91 3B AE 9A 01 41 04 9C 02 BF C9 7E
F2 36 CE 6D 8F E5 D9 40 13 C7 21 E9 15 98 2A CD
2B 12 B6 5D 9B 7D 59 E2 0A 84 20 05 F8 FC 4E 02
53 2E 87 3D 37 B9 6F 09 D6 D4 51 1A DA 8F 14 04
2F 46 61 4A 4C 70 C0 F1 4B EF F5

FF FF FF FF - sequence

Outputs:
02 - 2 Output Transactions

Output 1:
40 4B 4C 00 00 00 00 00 - 0.05 BTC (5000000)
19 - pk_script is 25 bytes long

76 A9 14 1A A0 CD 1C BE A6 E7 45 8A 7A BA D5 12 - pk_script
A9 D9 EA 1A FB 22 5E 88 AC

Output 2:
80 FA E9 C7 00 00 00 00 - 33.54 BTC (3354000000)
19 - pk_script is 25 bytes long

76 A9 14 0E AB 5B EA 43 6A 04 84 CF AB 12 48 5E - pk_script
FD A0 B7 8B 4E CC 52 88 AC

Locktime:
00 00 00 00 - lock time
</pre>

=== block ===

The '''block''' message is sent in response to a getdata message which requests transaction information from a block hash.

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 4 || version || uint32_t || Block version information, based upon the software version creating this block
|-
| 32 || prev_block || char[32] || The hash value of the previous block this particular block references
|-
| 32 || merkle_root || char[32] || The reference to a Merkle tree collection which is a hash of all transactions related to this block
|-
| 4 || timestamp || uint32_t || A timestamp recording when this block was created (Limited to 2106!)
|-
| 4 || bits || uint32_t || The calculated difficulty target being used for this block
|-
| 4 || nonce || uint32_t || The nonce used to generate this block… to allow variations of the header and compute different hashes
|-
| ? || txn_count || var_int || Number of transaction entries
|-
| ? || txns || tx[] || Block transactions, in format of "tx" command
|}

The SHA256 hash that identifies each block (and which must have a run of 0 bits) is calculated from the first 6 fields of this structure (version, prev_block, merkle_root, timestamp, bits, nonce, and standard SHA256 padding, making two 64-byte chunks in all) and ''not'' from the complete block. To calculate the hash, only two chunks need to be processed by the SHA256 algorithm. Since the ''nonce'' field is in the second chunk, the first chunk stays constant during mining and therefore only the second chunk needs to be processed. However, a Bitcoin hash is the hash of the hash, so two SHA256 rounds are needed for each mining iteration.

=== headers ===

The ''headers'' packet returns block headers in response to a ''getheaders'' packet.

Payload:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| ? || count || var_int || Number of block headers
|-
| 77x? || headers || block_header[] || Block headers
|}

=== getaddr ===

The getaddr message sends a request to a node asking for information about known active peers to help with identifying potential nodes in the network. The response to receiving this message is to transmit an addr message with one or more peers from a database of known active peers. The typical presumption is that a node is likely to be active if it has been sending a message within the last three hours.

No additional data is transmitted with this message.

=== checkorder ===

This message is used for [[IP Transactions]], to ask the peer if it accepts such transactions and allow it to look at the content of the order.

It contains a CWalletTx object

Payload:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
|colspan="4"| Fields from CMerkleTx
|-
| ? || hashBlock
|-
| ? || vMerkleBranch
|-
| ? || nIndex
|-
|colspan="4"| Fields from CWalletTx
|-
| ? || vtxPrev
|-
| ? || mapValue
|-
| ? || vOrderForm
|-
| ? || fTimeReceivedIsTxTime
|-
| ? || nTimeReceived
|-
| ? || fFromMe
|-
| ? || fSpent
|}

=== submitorder ===

Confirms an order has been submitted.

Payload:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 32 || hash || char[32] || Hash of the transaction
|-
| ? || wallet_entry || CWalletTx || Same payload as checkorder
|}

=== reply ===

Generic reply for [[IP Transactions]]

Payload:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| 4 || reply || uint32_t || reply code
|}

Possible values:

{|class="wikitable"
! Value !! Name !! Description
|-
| 0 || SUCCESS || The IP Transaction can proceed (''checkorder''), or has been accepted (''submitorder'')
|-
| 1 || WALLET_ERROR || AcceptWalletTransaction() failed
|-
| 2 || DENIED || IP Transactions are not accepted by this node
|}

=== ping ===

The ''ping'' message is sent primarily to confirm that the TCP/IP connection is still valid. An error in transmission is presumed to be a closed connection and the address is removed as a current peer. No reply is expected as a result of this message being sent nor any sort of action expected on the part of a client when it is used.

=== alert ===

An '''alert''' is sent between nodes to send a general notification message throughout the network. If the alert can be confirmed with the signature as having come from the the core development group of the Bitcoin software, the message is suggested to be displayed for end-users. Attempts to perform transactions, particularly automated transactions through the client, are suggested to be halted. The text in the Message string should be relayed to log files and any user interfaces.

Payload:

{|class="wikitable"
! Field Size !! Description !! Data type !! Comments
|-
| ? || message || var_str || System message which is coded to convey some information to all nodes in the network
|-
| ? || signature || var_str || A signature which can be confirmed with a public key verifying that it is Satoshi (the originator of Bitcoins) who has "authorized" or created the message
|}

The signature is to be compared to this ECDSA public key:

04fc9702847840aaf195de8442ebecedf5b095cdbb9bc716bda9110971b28a49e0ead8564ff0db22209e0374782c093bb899692d524e9d6a6956e7c5ecbcd68284
(hash) 1AGRxqDa5WjUKBwHB9XYEjmkv1ucoUUy1s

Source: [http://www.bitcoin.org/smf/index.php?topic=898.0]

== Scripting ==

See [[script]].

[[Category:Technical]]
[[Category:Developer]]

Help:Introduction

2011-03-01T10:53:04Z

Sahtor: fix 3 typos

<div class="plainlinks" style="border: 1px solid red; width: 100%; background-color: #fcc; padding: 10px; margin-bottom: 25px;">This page requires copy editing and improvement.</div>

Alice is far away from Bob and wants to buy his [http://www.grasshillalpacas.com/alpacaproductsforbitcoinoffer.html Alpaca socks]. In return, she wants to send him a dollar. A dollar bill is a piece of paper with very low intrinsic value, but which is accepted by people in exchange for valuable products and services in the real world, such as the socks Alice wants to buy. One simple thing Alice can do is to put a dollar bill in an envelope, mail it to Bob, and then wait for Bob to send the socks to her.

Another thing Alice can do is to "wire" the money to Bob. She can do that by first giving her dollar bills to an institution called a bank, the job of which is to safe-keep Alice's dollar bills and, in return, to give Alice a written promise (called a "bank statement") that, whenever she wishes, she can come to the bank to take back the same amount of dollar bills that she deposited. Since the money is still Alice's, she is entitled to do with it whatever she pleases, and the bank (like most banks), for a small fee, will do Alice the service of "giving" the dollar bills to Bob instead of her. This could be done by sending a person to Bob's door, with Alice's dollar bills in hand (or, better, fresh new dollar bills, if Alice's dollar bills are in bad condition), but usually it is done by Alice's bank by giving the dollar bills to Bob's bank and informing them that the money is for Bob, who will then see the amount in his next statement, or, if he is in a hurry, the next time he contacts his bank asking about how much money they have for him.

Since banks have many customers, and bank employees require money for doing the job of talking to people and signing documents, banks in recent times have been using machines such as ATMs and web servers, that do the job of "talking" to the customers instead of paid bank employees. The job of these machines is to learn what each customer wants to do with his/her money and, to the extent that it's possible, act on what the customer wants (for example, ATMs can hand cash). In the end, there is very little human involvement in this process, most of the time. The people can always know how much money out of the money that the bank is safe-keeping is theirs, and they are confident that the numbers they see in their bank statements and on their computer screens stand for the number of dollar bills that that they can get from the bank at any time they wish. They can be so sure of that, that they can accept those numbers in the same way they accept paper dollars (this is similar to the way people started accepting paper dollars as they accepted gold or silver).

However, the fact that machines are used does not change the structure of this system, which is, as it was, based on a central authority (the bank) which is responsible for keeping records about how much money belongs to whom. Everybody has to rely on this central authority to be honest (i.e. to say the truth about how much money they are safe-keeping in total, or at least to make the paper money available upon demand from the owners). Also, every person has to identify him/herself to this authority, by giving his/her real name, in order to be allowed to get their paper bills back or to send money to another person.

Bitcoin is a system of owning and voluntarily transferring amounts of so-called bitcoins, in a manner similar to an on-line banking interface, but anonymously and without reliance on a central authority to decide on what is true. These bitcoins are valuable because they require the spending of real resources (CPU time and electricity) to produce, and they cannot be counterfeited or removed from a person's ownership without illicit access to his/her computer.

==Preventing stealing==
To guarantee that an eavesdropper, Eve, cannot access other people's bitcoins by creating transactions in their names we use a [[Wikipedia:Public-key_cryptography|public key system]] to make digital signatures. In this system, each person, such as Alice and Bob, has a pair of public and private keys which he/she stores in a safe [[Wallet|wallet]]. Only the user with his secret private key can sign a document, such as the transaction to give some of his bitcoins to somebody else, but any one can validate the signature using the user’s public key.

* Bob sends his public key to Alice.
* Alice adds Bob’s public key along with the amount she wants to transfer, to the transaction.
* Alice signs the transaction with her secret private key.

As a result, anyone who knows the public keys of both Alice and Bob can now see that Alice agreed to transfer the amount to Bob, because nobody other than Alice has Alice's private key. Alice would be foolish to give her private key to other people, as this would allow them to sign transactions in her name, removing funds from her balance.

Later on, when Bob will transfer the same coins to Charley, he will do the same thing: receive from Charley his public key, add a new transaction to the chain of transactions and sign it with his (Bob) private key. But only Bob can do this, because only Bob has the private key which is necessary for signing and which is the only private key to match Bob’s public key that is already in the chain.

Eve cannot change who the coins belong to by replacing Bob’s public key with her public key, because Alice signed the transfer to Bob using her private key, declaring that the coins which belonged to her now belong to Bob, and Alice's private key is kept secret from Eve. So if Charley accepts that the original coin was in the hands of Alice he will also accept the fact that this coin was later passed to Bob and now Bob is passing this same coin to him.

==Preventing double-spending==
This is how we guarantee that Alice cannot replicate the coin and use it in more than one transaction:

* Details about the [[Transactions|transaction]] are [[Network|sent]] to as many other people's computers as possible.
* A chain of [[Blocks|blocks]] that contains a record of all transactions is collectively maintained by all computers (each has a full copy).
* Blocks are chained in a way that does not allow their data to be modified, without all following blocks becoming invalid.
* Valid blocks are computationally difficult to create and only valid blocks are allowed in the chain, containing valid transactions.
* When multiple continuations to this chain appear, the longest such branch is accepted as the correct one and built upon.

When Bob sees that his transaction has been included in a block, which has been made part of the longest and constantly growing block chain, he can be confident that the transaction by Alice has been accepted by other computers as valid and has been recorded, preventing Alice from creating a second transaction with the same coin.

In theory, Alice could generate a spoofed block in which her past usage of the same coin does not appear and try to send this block to everyone as evidence that the coin is still hers. However, that past transaction, which contains a signature from Alice, has already been announced, has already been distributed to a very large number of computers in the bitcoin network and a block containing it has already been generated by someone (otherwise, the first receiver of the coin would have no confirmation). Since the process of generating a block is designed to take a [[Proof_of_work|long time]] and all transactions must be given in such blocks, Alice will be unable to compete with all these computers in the rate at which she can generate blocks. Bob will receive much more blocks from third persons than Alice alone will ever be able to generate, and some of the newer blocks will contain Alice's previous transaction, telling Bob that Alice has already spent her coin. And since, in the presence of multiple parallel chains of blocks of transactions, the longest such chain is accepted and built upon, the only way for Alice to pass her own version of events is to be in a position to permanently command the majority of the CPU power on the network. We assume no single person or organization can do that and therefore, as long as the people who control the majority of the CPU power are acting honestly, accepting only valid blocks and always choosing the longest chain as the one to extend, Alice's transaction will be permanently recorded and Alice will be unable to create another transaction with the same coin.

==Anonymity==
Bitcoin "accounts" do not have people's names on them and do not have to correspond to individuals. Each balance is simply associated with a public-private key pair and the money "belongs" to whoever has the private key and can sign transactions with it. The transactions that are signed using those keys also don't have to include names.

Each person can have many such key pairs, each with its own balance, and this can make it more difficult to identify which person owns what amount. In order to protect his [[Anonymity|privacy]], Bob can even generate a new public-private key pair for each individual transaction. So David receiving the coin from Charley will not be able to identify who is the second person in the list of transactions. The only thing David will know is the [[Address|address]] of Bob which is a shortened (hashed) version of his public key.

==Creation of coins==
As we saw, both Bob and Charley need to verify that the original coin from Alice is valid. Alice cannot simply generate coins instantly, out of thin air, because the appearance of a coin is a transaction that needs to be accepted by others (it must appear at some place in the chain of blocks). The way that new coins are slowly introduced is this: every computer that manages to generate a block is allowed to put one transaction there in which it gains 50 BTC, without this amount having to come from somewhere. Other computers receiving the block can easily see that the block is valid and accept that this amount belongs to the computer that generated the block. This is called a "proof of work", because generating blocks is a [[Target|slow]] process that requires Alice to spend real resources (buy recent computer hardware, use electricity and CPU time) and in this way it can be compared to gold mining. Only with a proof of work is Alice allowed to contribute to the [[Block_chain|chain of blocks]] that together keep a record of all transactions. The coin received by Alice is an incentive for her to perform this computation work. In addition to this, Alice can shave a small, voluntary [[Transaction_fee|fee]] from the transactions stored in the block.

==Putting it all together==
Directly experience the system in action by visiting [http://blockexplorer.com/ Bitcoin Block Explorer].
The site shows you the latest blocks in the block chain. The [[Block_chain|block chain]] contains the agreed history of all transactions that took place in the system.
Note how many blocks were generated in the last hour, should be around 6. Also notice the number of transactions and the total amount transferred in the last hour (last time I checked it was about 64 and 15K.)
This should give you an indication of how active the system is.

Next, drill into one of these blocks.
Start by noticing that the block's [[hash|hash]] begins with a run of zeros, this is what made making it so difficult.
The computer that generated this block had to run on many ''Nonce'' values (also listed on the block's page) until it found one that generated this run of zeros.
Next notice the line titled ''Previous block'', each block contains the hash of the block that came before it, this is what forms the chain of blocks.
Now notice all the transactions the block contains. The first transaction is the income earned by the computer that generated this block. It includes a fixed amount of coins created out of thin air and possibly fee collected from other transactions in the same block.

Drill into any of the transactions and you will see how it is made from one or more amounts coming in and out.
The fact that there can be more than one incoming and outgoing amounts, allow the system to join and break amounts in any possible way allowing for any fractional amount needed (usually cents.)
Each incoming amount is a transaction from the past (which you can also drill to) coming from an address of someone
and each outgoing amount is addressed to someone and will be part of a future transaction (which you can also drill too if it also had already taken place.)

Finally you can drill into any of the [[Address|addresses]] and see what public information is available.

To get an impression of the amount of activity on the Bitcoin network, you might like to visit the monitoring websites [http://www.bitcoinwatch.com Bitcoin Watch] and [http://www.bitcoinmonitor.com Bitcoin Monitor]. The first has general statistics on the amount and size of transactions, while the latter shows a real-time visualization of events on the Bitcoin network.

==See Also==

* Installing Bitcoin [[getting started]]
* [[How bitcoin works]]
* [[Using Bitcoin]]
* A gentle introduction to Bitcoin - [[BitcoinMe]]
* Another introduction, ''The Rebooting Of Money'' podcast is found at [[Bitcoin Money]]

User:Sahtor

2011-03-01T10:41:02Z

Sahtor: Created page with "Contributors Award participant: 12SMnMJ35WKRAEeYfmgmH71CYrkiFtZUd2 ==Contact== * email: sahtor@gmail.com * Twitter: [http://twitter.com/Sahtor @Sahtor]"

Contributors Award participant: 12SMnMJ35WKRAEeYfmgmH71CYrkiFtZUd2

==Contact==
* email: sahtor@gmail.com
* Twitter: [http://twitter.com/Sahtor @Sahtor]