Difference between revisions of "Bitcoin XT"

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(Numerous corrections; remove bits about double-spend relaying since it doesn't actually work.)
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|author=[[Gavin Andresen]]<br/>[[Mike Hearn]]
 
|author=[[Gavin Andresen]]<br/>[[Mike Hearn]]
 
|website=[https://bitcoinxt.software bitcoinxt.software]
 
|website=[https://bitcoinxt.software bitcoinxt.software]
}}'''Bitcoin XT''' is a fork of [[Bitcoin Core]] that aims to make transactions reliable, inexpensive, and accessible. It achieved significant support after adopting [[BIP 0101]], making it an important proponent of the [[block size limit controversy]].<ref>{{cite web|work=[[The Neighbourhood Pool Watch]]|author=[[organofcorti]]|title=BIP101 implementation flaws|date=27 August 2015|accessdate=27 August 2015|url=http://organofcorti.blogspot.com/2015/08/bip101-implementation-flaws.html}}</ref>
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}}'''Bitcoin XT''' is a fork of [[Bitcoin Core]] that aims to make transactions reliable, inexpensive, and accessible. It achieved significant support after prematurely adopting [[BIP 0101|BIP 101]], making it an important proponent of the [[block size limit controversy]].<ref>{{cite web|work=[[The Neighbourhood Pool Watch]]|author=[[organofcorti]]|title=BIP101 implementation flaws|date=27 August 2015|accessdate=27 August 2015|url=http://organofcorti.blogspot.com/2015/08/bip101-implementation-flaws.html}}</ref>
  
After the inauguration of [[Wladimir van der Laan]] to the position of [[Core maintainer]], Bitcoin XT was organized{{when}} by [[Gavin Andresen]] and [[Mike Hearn]] to address controversial ideas lacking the consensus required by Laan to be implemented in Bitcoin Core.<ref>{{cite web|work=Medium|title=An XT FAQ|author=[[Mike Hearn|Hearn, Mike]]|date=27 August 2015|accessdate=27 August 2015|url=https://medium.com/@octskyward/an-xt-faq-38e78aa32ff0}}</ref>
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After the inauguration of [[Wladimir van der Laan]] to the position of [[Core maintainer]], Bitcoin XT was organized{{when}} by [[Gavin Andresen]] and [[Mike Hearn]] to address controversial ideas lacking the consensus required to be implemented in Bitcoin Core.<ref>{{cite web|work=Medium|title=An XT FAQ|author=[[Mike Hearn|Hearn, Mike]]|date=27 August 2015|accessdate=27 August 2015|url=https://medium.com/@octskyward/an-xt-faq-38e78aa32ff0}}</ref>
  
Once 75% of the last 1000 blocks are observed to be in support of XT, a [[hardfork]] will occur and XT nodes will separate from the rest of the network, implementing several changes, most notably an increase in block size.
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Due to implementing BIP 101 in version 0.11.0A, it is now incompatible with the Bitcoin consensus protocol, and when 75% of the last 1000 blocks are observed to have particular version bits set, it ceases enforcing the 1 MB block size limit and also adds a few new rules.
 +
Since it is incompatible with the Bitcoin protocol, it is technically an [[altcoin]], but due to an unusually large economy acceptance may potentially become a "new Bitcoin" some day and is therefore (for now) being tolerated on the wiki.
  
 
==Mission statement==
 
==Mission statement==
 
<!--this needs to be summarized or removed-->
 
<!--this needs to be summarized or removed-->
The XT mission statement defines what the project believes is important: commitment to these principles are what differentiates us from Bitcoin Core. We try to follow Satoshi's original vision, as it is that vision which brought the Bitcoin community together.
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The XT mission statement defines what the project believes is important: commitment to these principles are what differentiates it from Bitcoin Core.
  
* '''Scaling the network up to handle user demand is important''', even if that means the network changes along the way. It's what Satoshi wanted<ref>[http://satoshi.nakamotoinstitute.org/emails/cryptography/2/ Re: Bitcoin P2P e-cash paper]</ref> and the idea of a global system used by ordinary people is what motivated many of us to join him.
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* '''Scaling the network up to handle user demand and spam is important''', even if that means the network becomes centralised along the way. The idea of a global system used by ordinary people is what motivated many people to support this.
* '''XT provides people with information they need''', even if using it requires them to make risk based decisions. For example:
+
* XT proponents believe '''unconfirmed transactions are important'''. Many merchants want or need to accept payments within seconds rather than minutes or hours. XT accepts this fact and does what it can to minimise the risk, then "helps" sellers judge what remains. It is committed to support only "first seen" policies, and will not adopt changes that make unconfirmed transactions riskier.
** We believe '''unconfirmed transactions are important'''. Many merchants want or need to accept payments within seconds rather than minutes or hours. XT accepts this fact and does what it can to minimise the risk, then help sellers judge what remains. It is committed to the first seen rule<ref>[http://satoshi.nakamotoinstitute.org/emails/cryptography/8/ Re: Bitcoin P2P e-cash paper]</ref>. We will not adopt changes that make unconfirmed transactions riskier.
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<!-- This doesn't seem different from Core: ** '''Lightweight wallets are important'''. Most users cannot or will not run a fully verifying node. Most of the world population does not even own a computer: they will experience the internet exclusively via smartphones. These users must sacrifice some security in order to participate, so XT supports whatever technical tradeoffs wallet developers wish to explore. -->
** '''Lightweight wallets are important'''. Most users cannot or will not run a fully verifying node. Most of the world population does not even own a computer: they will experience the internet exclusively via smartphones. These users must sacrifice some security in order to participate, so XT supports whatever technical tradeoffs wallet developers wish to explore.
 
 
* '''Decision making is quick and clear'''. Decisions are made according to a leadership hierarchy. The XT software encodes decisions that follow the above principles: people who disagree are welcome to use different software, or patch ours. We do not consider writing principled software to be centralising and do not refuse to select reasonable defaults.
 
* '''Decision making is quick and clear'''. Decisions are made according to a leadership hierarchy. The XT software encodes decisions that follow the above principles: people who disagree are welcome to use different software, or patch ours. We do not consider writing principled software to be centralising and do not refuse to select reasonable defaults.
* The Bitcoin XT community is friendly, pragmatic, cares about app developers and considers the user experience in everything we do. We value professionalism in technical approach and communication. We run a moderated mailing list and do not tolerate troublemakers.
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<!-- Also no difference: * The Bitcoin XT community is friendly, pragmatic, cares about app developers and considers the user experience in everything we do. We value professionalism in technical approach and communication. We run a moderated mailing list and do not tolerate troublemakers. -->
  
 
You can [https://bitcoinxt.software/patches.html read more about the code changes in Bitcoin XT].  
 
You can [https://bitcoinxt.software/patches.html read more about the code changes in Bitcoin XT].  
  
 
==Block size hard fork==
 
==Block size hard fork==
In 2010, a block size limit was introduced into Bitcoin by [[Satoshi Nakamoto]]. He added it as a safety measure and meant for it to be removed once lightweight wallets were developed; however, this was never done. It is expected that soon Bitcoin will be out of capacity and experiencing reliability problems as a result. Bitcoin Core has not yet implemented a measure to increase the block size limit, so miners and users who disagree with them must either switch to Bitcoin XT, or apply the bigblocks patches<ref>[https://github.com/bitcoinxt/bitcoinxt/tree/only-bigblocks Big blocks patches on GitHub]</ref> manually.<!--mention bip 100-->
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In 2010, a block size limit was introduced into Bitcoin by [[Satoshi Nakamoto]]. He added it as a safety measure to prevent miners from spamming large blocks and meant for it to be removed once secure lightweight wallets were developed;
 +
however, the spam problem has only gotten worse, and secure lightweight wallets never implemented.
  
 
There has been much community [[Block size limit controversy|debate]] on this topic. You can read analysis and explanations for why we think raising the block size limit is important here:  
 
There has been much community [[Block size limit controversy|debate]] on this topic. You can read analysis and explanations for why we think raising the block size limit is important here:  
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==Miners==
 
==Miners==
Miners that side with Bitcoin XT will produce blocks with a new version number.<ref name="avc">{{cite web|title=The Bitcoin XT Fork|work=AVC|author=Wilson, Fred|date=17 August 2015|accessdate=28 August 2015|url=http://avc.com/2015/08/the-bitcoin-xt-fork/}}</ref> This indicates to the rest of the network that they support XT.<ref name="avc"/> When 75% of the last 1000 blocks are new-version blocks, a decision will have been reached to start building larger blocks that will be rejected by Bitcoin Core nodes.<ref name="avc"/> This will begin after a waiting period of two weeks to allow news of the new consensus to spread and allow anyone who hasn't upgraded yet to do so.<ref name="avc"/> During this time, existing Bitcoin Core nodes will be [[alert system|printing a message]] notifying the operators about the availability of an upgraded version.<ref name="avc"/>
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Miners that side with Bitcoin XT will produce blocks with a new version number.<ref name="avc">{{cite web|title=The Bitcoin XT Fork|work=AVC|author=Wilson, Fred|date=17 August 2015|accessdate=28 August 2015|url=http://avc.com/2015/08/the-bitcoin-xt-fork/}}</ref> This indicates to the rest of the network that they support XT.<ref name="avc"/> When 75% of the last 1000 blocks are new-version blocks, these miners will automatically abandon Bitcoin and begin mining on a new Bitcoin XT blockchain.<ref name="avc"/> This will begin after a waiting period of two weeks in hopes the economy in this time may force anyone who hasn't switched yet to do so.<ref name="avc"/>
  
If the hard fork occurs and you are still mining with Bitcoin Core, your node will reject the first new block that is larger than one megabyte in size. At that point there is a risk your newly mined coins will not be accepted at major exchanges or merchants.  
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Users and miners running full Bitcoin nodes will reject the XT blockchain starting with its first block that is larger than one megabyte in size, and thus be unaffected provided it fails to achieve economic consensus.
  
 
==Users and merchants==
 
==Users and merchants==
If insufficient mining hash power runs XT to reach supermajority then nothing will happen. If enough does, you will follow the new chain and things will continue as normal.
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If insufficient mining hash power runs XT to reach supermajority then nothing will happen. If enough does, XT users will follow a new blockchain and cease to be using and trading bitcoins.
 
 
Additionally, XT has a useful feature: double spend monitoring and relaying. By running XT you help propagate information about double spends across the network, making it harder for payment fraudsters to steal from sellers by broadcasting two conflicting transactions simultaneously.
 
  
 
==See Also==
 
==See Also==

Revision as of 05:19, 31 August 2015

Bitcoin XT
Xt.png
Bitcoinxt.png
The identifying marks of an XT client
Original authorsGavin Andresen
Mike Hearn
Websitebitcoinxt.software
Bitcoin XT is a fork of Bitcoin Core that aims to make transactions reliable, inexpensive, and accessible. It achieved significant support after prematurely adopting BIP 101, making it an important proponent of the block size limit controversy.[1]

After the inauguration of Wladimir van der Laan to the position of Core maintainer, Bitcoin XT was organized[when?] by Gavin Andresen and Mike Hearn to address controversial ideas lacking the consensus required to be implemented in Bitcoin Core.[2]

Due to implementing BIP 101 in version 0.11.0A, it is now incompatible with the Bitcoin consensus protocol, and when 75% of the last 1000 blocks are observed to have particular version bits set, it ceases enforcing the 1 MB block size limit and also adds a few new rules. Since it is incompatible with the Bitcoin protocol, it is technically an altcoin, but due to an unusually large economy acceptance may potentially become a "new Bitcoin" some day and is therefore (for now) being tolerated on the wiki.

Mission statement

The XT mission statement defines what the project believes is important: commitment to these principles are what differentiates it from Bitcoin Core.

  • Scaling the network up to handle user demand and spam is important, even if that means the network becomes centralised along the way. The idea of a global system used by ordinary people is what motivated many people to support this.
  • XT proponents believe unconfirmed transactions are important. Many merchants want or need to accept payments within seconds rather than minutes or hours. XT accepts this fact and does what it can to minimise the risk, then "helps" sellers judge what remains. It is committed to support only "first seen" policies, and will not adopt changes that make unconfirmed transactions riskier.
  • Decision making is quick and clear. Decisions are made according to a leadership hierarchy. The XT software encodes decisions that follow the above principles: people who disagree are welcome to use different software, or patch ours. We do not consider writing principled software to be centralising and do not refuse to select reasonable defaults.

You can read more about the code changes in Bitcoin XT.

Block size hard fork

In 2010, a block size limit was introduced into Bitcoin by Satoshi Nakamoto. He added it as a safety measure to prevent miners from spamming large blocks and meant for it to be removed once secure lightweight wallets were developed; however, the spam problem has only gotten worse, and secure lightweight wallets never implemented.

There has been much community debate on this topic. You can read analysis and explanations for why we think raising the block size limit is important here:

Miners

Miners that side with Bitcoin XT will produce blocks with a new version number.[3] This indicates to the rest of the network that they support XT.[3] When 75% of the last 1000 blocks are new-version blocks, these miners will automatically abandon Bitcoin and begin mining on a new Bitcoin XT blockchain.[3] This will begin after a waiting period of two weeks in hopes the economy in this time may force anyone who hasn't switched yet to do so.[3]

Users and miners running full Bitcoin nodes will reject the XT blockchain starting with its first block that is larger than one megabyte in size, and thus be unaffected provided it fails to achieve economic consensus.

Users and merchants

If insufficient mining hash power runs XT to reach supermajority then nothing will happen. If enough does, XT users will follow a new blockchain and cease to be using and trading bitcoins.

See Also

References