Proof of work - Revision history

Furunodo: /* Consensus */ removed

2020-06-06T13:54:33Z

Consensus: removed

← Older revision		Revision as of 13:54, 6 June 2020
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	# [[Proof of Burn]]		# [[Proof of Burn]]

	~~=== Consensus ===~~
	~~# [https://www.stellar.org/papers/stellar-consensus-protocol.pdf Stellar Consensus Protocol]~~

	[[Category:Vocabulary]]		[[Category:Vocabulary]]

Luke-jr: /* List of algorithms */ Remove altcoin promotion

2019-04-24T00:41:00Z

List of algorithms: Remove altcoin promotion

← Older revision		Revision as of 00:41, 24 April 2019
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	# [[Momentum]] birthday collision		# [[Momentum]] birthday collision
	# Cuckoo Cycle proof of work https://github.com/tromp/cuckoo		# Cuckoo Cycle proof of work https://github.com/tromp/cuckoo
	# Various other proof of works functions ~~(e.g. [[Ethereum]] had a few candidates)~~		# Various other proof of works functions

	=== Proof of X ===		=== Proof of X ===

Belcher: /* Example */ Change example to be clearer and not talk about leading zeros of a hash

2018-11-14T13:55:13Z

Example: Change example to be clearer and not talk about leading zeros of a hash

← Older revision		Revision as of 13:55, 14 November 2018
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	== Example ==		== Example ==

	Let's say the base string that we are going to do work on is "Hello, world!". Our target is to find a variation of it that SHA-256 hashes to a value ~~beginning with '000'~~. We vary the string by adding an integer value to the end called a [[nonce]] and incrementing it each time. Finding a match for "Hello, world!" takes us 4251 tries ~~(but happens to have zeroes in the first four digits):~~		Let's say the base string that we are going to do work on is "Hello, world!". Our target is to find a variation of it that SHA-256 hashes to a value smaller than 2^240. We vary the string by adding an integer value to the end called a [[nonce]] and incrementing it each time, then interpreting the hash result as a long integer and checking whether it's smaller than the target 2^240. Finding a match for "Hello, world!" takes us 4251 tries.

	"Hello, world!0" => 1312af178c253f84028d480a6adc1e25e81caa44c749ec81976192e2ec934c64		"Hello, world!0" => 1312af178c253f84028d480a6adc1e25e81caa44c749ec81976192e2ec934c64 = 2^252.253458683
	"Hello, world!1" => e9afc424b79e4f6ab42d99c81156d3a17228d6e1eef4139be78e948a9332a7d8		"Hello, world!1" => e9afc424b79e4f6ab42d99c81156d3a17228d6e1eef4139be78e948a9332a7d8 = 2^255.868431117
	"Hello, world!2" => ae37343a357a8297591625e7134cbea22f5928be8ca2a32aa475cf05fd4266b7		"Hello, world!2" => ae37343a357a8297591625e7134cbea22f5928be8ca2a32aa475cf05fd4266b7 = 2^255.444730341
	...		...
	"Hello, world!4248" => 6e110d98b388e77e9c6f042ac6b497cec46660deef75a55ebc7cfdf65cc0b965		"Hello, world!4248" => 6e110d98b388e77e9c6f042ac6b497cec46660deef75a55ebc7cfdf65cc0b965 = 2^254.782233115
	"Hello, world!4249" => c004190b822f1669cac8dc37e761cb73652e7832fb814565702245cf26ebb9e6		"Hello, world!4249" => c004190b822f1669cac8dc37e761cb73652e7832fb814565702245cf26ebb9e6 = 2^255.585082774
	"Hello, world!4250" => 0000c3af42fc31103f1fdc0151fa747ff87349a4714df7cc52ea464e12dcd4e9		"Hello, world!4250" => 0000c3af42fc31103f1fdc0151fa747ff87349a4714df7cc52ea464e12dcd4e9 = 2^239.61238653

	4251 hashes on a modern computer is not very much work (most computers can achieve at least 4 million hashes per second). Bitcoin automatically varies the [[~~difficulty~~]] (and thus the amount of work required to generate a block) to keep a roughly constant rate of block generation.		4251 hashes on a modern computer is not very much work (most computers can achieve at least 4 million hashes per second). Bitcoin automatically varies the [[target]] (and thus the amount of work required to generate a block) to keep a roughly constant rate of block generation.

	In Bitcoin ~~things are~~ a ~~bit more complex~~, ~~especially since the~~ header contains the [[Protocol_documentation#Merkle_Trees\|Merkle tree]] which depends on the included [[transactions]]. This includes the generation transaction, a transaction "out of nowhere" to our own address, which in addition to providing the miner with incentive to do the work, also ensures that every miner hashes a unique data set.		In Bitcoin the hash value is also used as a reference to the block itself, so somebody might say that their [[transaction]] has been mined into [[block]] with hash <code>0000c3af42fc31103f1fdc0151fa747ff87349a4714df7cc52ea464e12dcd4e9</code>. The [[header]] of a [[block]] contains the [[Protocol_documentation#Merkle_Trees\|Merkle tree]] which depends on the included [[transactions]]. This includes the generation transaction, a transaction "out of nowhere" to our own address, which in addition to providing the miner with incentive to do the work, also ensures that every miner hashes a unique data set.

	== List of algorithms ==		== List of algorithms ==

Belcher: Added catagory technical

2016-05-15T03:06:14Z

Added catagory technical

← Older revision		Revision as of 03:06, 15 May 2016
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	[[Category:Vocabulary]]		[[Category:Vocabulary]]
	[[Category:Proof-of-x]]		[[Category:Proof-of-x]]
			[[Category:Technical]]

	[[fr:Preuve de travail]]		[[fr:Preuve de travail]]

JonathanCross: Linking to new SHA-256 page, Merkle tree, adding some Wikipedia links for other hash functions, removing second (Wikipedia) link to Hashcash as we already have an internal link above.

2016-01-29T16:20:05Z

Linking to new SHA-256 page, Merkle tree, adding some Wikipedia links for other hash functions, removing second (Wikipedia) link to Hashcash as we already have an internal link above.

← Older revision		Revision as of 16:20, 29 January 2016
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	A '''proof of work''' is a piece of data which is difficult (costly, time-consuming) to produce but easy for others to verify and which satisfies certain requirements. Producing a proof of work can be a random process with low probability so that a lot of trial and error is required ''on average'' before a valid proof of work is generated. Bitcoin uses the [[Hashcash]] proof of work.		A '''proof of work''' is a piece of data which is difficult (costly, time-consuming) to produce but easy for others to verify and which satisfies certain requirements. Producing a proof of work can be a random process with low probability so that a lot of trial and error is required ''on average'' before a valid proof of work is generated. Bitcoin uses the [[Hashcash]] proof of work system.

	One application of this idea is using ~~[http://en.wikipedia.org/wiki/~~Hashcash ~~hashcash]~~ as a method to preventing email spam, requiring a proof of work on the email's contents (including the To address), on every email. Legitimate emails will be able to do the work to generate the proof easily (not much work is required for a single email), but mass spam emailers will have difficulty generating the required proofs (which would require huge computational resources).		One application of this idea is using Hashcash as a method to preventing email spam, requiring a proof of work on the email's contents (including the To address), on every email. Legitimate emails will be able to do the work to generate the proof easily (not much work is required for a single email), but mass spam emailers will have difficulty generating the required proofs (which would require huge computational resources).

	Hashcash proofs of work are used in Bitcoin for block generation. In order for a block to be accepted by network participants, [[Mining\|miners]] must complete a proof of work which covers all of the data in the block. The [[difficulty]] of this work is adjusted so as to limit the rate at which new blocks can be generated by the network to one every 10 minutes. Due to the very low probability of successful generation, this makes it unpredictable which worker computer in the network will be able to generate the next block.		Hashcash proofs of work are used in Bitcoin for block generation. In order for a block to be accepted by network participants, [[Mining\|miners]] must complete a proof of work which covers all of the data in the block. The [[difficulty]] of this work is adjusted so as to limit the rate at which new blocks can be generated by the network to one every 10 minutes. Due to the very low probability of successful generation, this makes it unpredictable which worker computer in the network will be able to generate the next block.
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	For a block to be valid it must hash to a value less than the current [[target]]; this means that each block indicates that work has been done generating it. Each block contains the hash of the preceding block, thus each block has a [[block chain\|chain]] of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.		For a block to be valid it must hash to a value less than the current [[target]]; this means that each block indicates that work has been done generating it. Each block contains the hash of the preceding block, thus each block has a [[block chain\|chain]] of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.

	The most widely used proof-of-work scheme is based on [~~https://en.wikipedia.org/wiki/SHA-2~~ SHA-256] and was introduced as a part of [[Bitcoin]]. Some other hashing algorithms that are used for proof-of-work include ~~scrypt~~, Blake-256, CryptoNight,~~<ref>~~[https://~~cryptonote~~.~~org~~/~~inside~~.~~php#equal-proof-of-work Equal Proof-of-Work~~], ~~Cryptonote~~.org</~~ref> HEFTY1, Quark,~~ SHA-3, scrypt-jane, scrypt-n, and combinations thereof.		The most widely used proof-of-work scheme is based on [[SHA-256]] and was introduced as a part of [[Bitcoin]]. Some other hashing algorithms that are used for proof-of-work include [https://en.wikipedia.org/wiki/Scrypt Scrypt], [https://en.wikipedia.org/wiki/BLAKE_(hash_function) Blake-256], [[CryptoNight]], [https://heavycoin.github.io/ HEFTY1], [https://131002.net/quark/quark_full.pdf Quark], [https://en.wikipedia.org/wiki/SHA-3 SHA-3], [https://github.com/floodyberry/scrypt-jane scrypt-jane], scrypt-n, and combinations thereof.

	== Example ==		== Example ==
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	4251 hashes on a modern computer is not very much work (most computers can achieve at least 4 million hashes per second). Bitcoin automatically varies the [[difficulty]] (and thus the amount of work required to generate a block) to keep a roughly constant rate of block generation.		4251 hashes on a modern computer is not very much work (most computers can achieve at least 4 million hashes per second). Bitcoin automatically varies the [[difficulty]] (and thus the amount of work required to generate a block) to keep a roughly constant rate of block generation.

	In Bitcoin things are a bit more complex, especially since the header contains the [~~http://en.wikipedia.org/wiki/Merkle_tree~~ Merkle tree] which depends on the included [[transactions]]. This includes the generation transaction, a transaction "out of nowhere" to our own address, which in addition to providing the miner with incentive to do the work, also ensures that every miner hashes a unique data set.		In Bitcoin things are a bit more complex, especially since the header contains the [[Protocol_documentation#Merkle_Trees\|Merkle tree]] which depends on the included [[transactions]]. This includes the generation transaction, a transaction "out of nowhere" to our own address, which in addition to providing the miner with incentive to do the work, also ensures that every miner hashes a unique data set.

	== List of algorithms ==		== List of algorithms ==

CryptoPrincess: added consensus and Stellar Consensus Protocol to the list of other algorithms.

2016-01-20T19:31:41Z

added consensus and Stellar Consensus Protocol to the list of other algorithms.

← Older revision		Revision as of 19:31, 20 January 2016
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	# [[Proof of Stake]]		# [[Proof of Stake]]
	# [[Proof of Burn]]		# [[Proof of Burn]]

			=== Consensus ===
			# [https://www.stellar.org/papers/stellar-consensus-protocol.pdf Stellar Consensus Protocol]

	[[Category:Vocabulary]]		[[Category:Vocabulary]]

Atheros: Rewrote two opening sentences to sound more like a human wrote them.

2015-08-26T06:20:15Z

Rewrote two opening sentences to sound more like a human wrote them.

← Older revision		Revision as of 06:20, 26 August 2015
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	A '''proof of work''' is a piece of data which ~~was~~ difficult (costly, time-consuming) to produce ~~so as~~ to ~~satisfy~~ certain ~~requirements. It must be trivial to check whether data satisfies said~~ requirements. Producing a proof of work can be a random process with low probability, so that a lot of trial and error is required ''on average'' before a valid proof of work is generated. Bitcoin uses the [[Hashcash]] proof of work.		A '''proof of work''' is a piece of data which is difficult (costly, time-consuming) to produce but easy for others to verify and which satisfies certain requirements. Producing a proof of work can be a random process with low probability so that a lot of trial and error is required ''on average'' before a valid proof of work is generated. Bitcoin uses the [[Hashcash]] proof of work.

	One application of this idea is using [http://en.wikipedia.org/wiki/Hashcash hashcash] as a method to preventing email spam, requiring a proof of work on the email's contents (including the To address), on every email. Legitimate emails will be able to do the work to generate the proof easily (not much work is required for a single email), but mass spam emailers will have difficulty generating the required proofs (which would require huge computational resources).		One application of this idea is using [http://en.wikipedia.org/wiki/Hashcash hashcash] as a method to preventing email spam, requiring a proof of work on the email's contents (including the To address), on every email. Legitimate emails will be able to do the work to generate the proof easily (not much work is required for a single email), but mass spam emailers will have difficulty generating the required proofs (which would require huge computational resources).

Atheros: linkify SHA-256 because people really don't know what hashing algorithms are. From that page they can click "Cryptographic hash function"

2015-08-26T06:14:19Z

linkify SHA-256 because people really don't know what hashing algorithms are. From that page they can click "Cryptographic hash function"

← Older revision		Revision as of 06:14, 26 August 2015
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	For a block to be valid it must hash to a value less than the current [[target]]; this means that each block indicates that work has been done generating it. Each block contains the hash of the preceding block, thus each block has a [[block chain\|chain]] of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.		For a block to be valid it must hash to a value less than the current [[target]]; this means that each block indicates that work has been done generating it. Each block contains the hash of the preceding block, thus each block has a [[block chain\|chain]] of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.

	The most widely used proof-of-work scheme is SHA-256~~, which~~ was introduced by [[Bitcoin]]. Some other hashing algorithms that are used for proof-of-work include scrypt, Blake-256, CryptoNight,<ref>[https://cryptonote.org/inside.php#equal-proof-of-work Equal Proof-of-Work], Cryptonote.org</ref> HEFTY1, Quark, SHA-3, scrypt-jane, scrypt-n, and combinations thereof.		The most widely used proof-of-work scheme is based on [https://en.wikipedia.org/wiki/SHA-2 SHA-256] and was introduced as a part of [[Bitcoin]]. Some other hashing algorithms that are used for proof-of-work include scrypt, Blake-256, CryptoNight,<ref>[https://cryptonote.org/inside.php#equal-proof-of-work Equal Proof-of-Work], Cryptonote.org</ref> HEFTY1, Quark, SHA-3, scrypt-jane, scrypt-n, and combinations thereof.

	== Example ==		== Example ==

Atheros: Made passive sentence active.

2015-08-26T05:37:18Z

Made passive sentence active.

← Older revision		Revision as of 05:37, 26 August 2015
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	One application of this idea is using [http://en.wikipedia.org/wiki/Hashcash hashcash] as a method to preventing email spam, requiring a proof of work on the email's contents (including the To address), on every email. Legitimate emails will be able to do the work to generate the proof easily (not much work is required for a single email), but mass spam emailers will have difficulty generating the required proofs (which would require huge computational resources).		One application of this idea is using [http://en.wikipedia.org/wiki/Hashcash hashcash] as a method to preventing email spam, requiring a proof of work on the email's contents (including the To address), on every email. Legitimate emails will be able to do the work to generate the proof easily (not much work is required for a single email), but mass spam emailers will have difficulty generating the required proofs (which would require huge computational resources).

	Hashcash proofs of work are used in Bitcoin for block generation. ~~Proofs~~ of work ~~that are tied to~~ the data ~~of each~~ block ~~are required for the blocks to be accepted~~. The [[difficulty]] of this work is adjusted so as to limit the rate at which new blocks can be generated by the network to one every 10 minutes. Due to the very low probability of successful generation, this makes it unpredictable which worker computer in the network will be able to generate the next block.		Hashcash proofs of work are used in Bitcoin for block generation. In order for a block to be accepted by network participants, [[Mining\|miners]] must complete a proof of work which covers all of the data in the block. The [[difficulty]] of this work is adjusted so as to limit the rate at which new blocks can be generated by the network to one every 10 minutes. Due to the very low probability of successful generation, this makes it unpredictable which worker computer in the network will be able to generate the next block.

	For a block to be valid it must hash to a value less than the current [[target]]; this means that each block indicates that work has been done generating it. Each block contains the hash of the preceding block, thus each block has a [[block chain\|chain]] of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.		For a block to be valid it must hash to a value less than the current [[target]]; this means that each block indicates that work has been done generating it. Each block contains the hash of the preceding block, thus each block has a [[block chain\|chain]] of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.

Atheros: removed broken link

2015-08-26T05:30:27Z

removed broken link

← Older revision		Revision as of 05:30, 26 August 2015
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	For a block to be valid it must hash to a value less than the current [[target]]; this means that each block indicates that work has been done generating it. Each block contains the hash of the preceding block, thus each block has a [[block chain\|chain]] of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.		For a block to be valid it must hash to a value less than the current [[target]]; this means that each block indicates that work has been done generating it. Each block contains the hash of the preceding block, thus each block has a [[block chain\|chain]] of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.

	The most widely used proof-of-work scheme is SHA-256, which was introduced by [[Bitcoin]]. Some other hashing algorithms that are used for proof-of-work include scrypt, Blake-256, CryptoNight,<ref>[https://cryptonote.org/inside.php#equal-proof-of-work Equal Proof-of-Work], Cryptonote.org</ref> HEFTY1, Quark, SHA-3, scrypt-jane, scrypt-n, and combinations.		The most widely used proof-of-work scheme is SHA-256, which was introduced by [[Bitcoin]]. Some other hashing algorithms that are used for proof-of-work include scrypt, Blake-256, CryptoNight,<ref>[https://cryptonote.org/inside.php#equal-proof-of-work Equal Proof-of-Work], Cryptonote.org</ref> HEFTY1, Quark, SHA-3, scrypt-jane, scrypt-n, and combinations thereof.

	== Example ==		== Example ==
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	"Hello, world!4250" => 0000c3af42fc31103f1fdc0151fa747ff87349a4714df7cc52ea464e12dcd4e9		"Hello, world!4250" => 0000c3af42fc31103f1fdc0151fa747ff87349a4714df7cc52ea464e12dcd4e9

	4251 hashes on a modern computer is not very much work (most computers can achieve at least 4 million hashes per second). Bitcoin automatically varies the [[difficulty]] (and thus the amount of work required to generate a block) to keep a roughly constant rate of block generation~~. The probability of a single hash succeeding can be found [http://blockexplorer.com/q/probability here]~~.		4251 hashes on a modern computer is not very much work (most computers can achieve at least 4 million hashes per second). Bitcoin automatically varies the [[difficulty]] (and thus the amount of work required to generate a block) to keep a roughly constant rate of block generation.

	In Bitcoin things are a bit more complex, especially since the header contains the [http://en.wikipedia.org/wiki/Merkle_tree Merkle tree] which depends on the included [[transactions]]. This includes the generation transaction, a transaction "out of nowhere" to our own address, which in addition to providing the miner with incentive to do the work, also ensures that every miner hashes a unique data set.		In Bitcoin things are a bit more complex, especially since the header contains the [http://en.wikipedia.org/wiki/Merkle_tree Merkle tree] which depends on the included [[transactions]]. This includes the generation transaction, a transaction "out of nowhere" to our own address, which in addition to providing the miner with incentive to do the work, also ensures that every miner hashes a unique data set.