Bitcoin Core - Revision history

AllEd01: grammar, spelling

2022-09-26T07:50:32Z

grammar, spelling

Tris T7: edit ref

2022-04-08T16:14:11Z

edit ref

← Older revision		Revision as of 16:14, 8 April 2022
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	'''Bitcoin Core''' (formerly '''Bitcoin-Qt''') is the third [[Bitcoin]] [[Clients\|client]], developed by [[Wladimir van der Laan]] based on the original reference code by [[Satoshi Nakamoto]].<ref>https://gavintech.blogspot.co.uk/2012/03/full-disclosure-bitcoin-qt-on-windows.html, Full disclosure: Bitcoin-Qt on Windows vulnerability, 21st October 2012</ref><ref>https://nvd.nist.gov/vuln/detail/CVE-2012-4682, Vulnerability Summary for CVE-2012-4682, 21st October 2012</ref> It has been bundled with [[bitcoind]] since version 0.5. Bitcoin-Qt has been rebranded to '''[[Bitcoin Core]]''' since version 0.9.0 <ref name="Rebranding to Bitcoin Core">{{cite web\|title=Bitcoin Core version 0.9.0 released\|url=https://bitcoin.org/en/release/v0.9.0\|publisher=Bitcoin.org\|accessdate=19 March 2014}}</ref>.		'''Bitcoin Core''' (formerly '''Bitcoin-Qt''') is the third [[Bitcoin]] [[Clients\|client]], developed by [[Wladimir van der Laan]] based on the original reference code by [[Satoshi Nakamoto]].<ref>https://gavintech.blogspot.co.uk/2012/03/full-disclosure-bitcoin-qt-on-windows.html, Full disclosure: Bitcoin-Qt on Windows vulnerability, 21st October 2012</ref><ref>https://nvd.nist.gov/vuln/detail/CVE-2012-4682, Vulnerability Summary for CVE-2012-4682, 21st October 2012</ref> It has been bundled with [[bitcoind]] since version 0.5. Bitcoin-Qt has been rebranded to '''[[Bitcoin Core]]''' since version 0.9.0.<ref name="Rebranding to Bitcoin Core">{{cite web\|title=Bitcoin Core version 0.9.0 released\|url=https://bitcoin.org/en/release/v0.9.0\|publisher=Bitcoin.org\|accessdate=19 March 2014}}</ref>

	Bitcoin Core can be used as a desktop client for regular payments or as a server utility for merchants and other payment services.		Bitcoin Core can be used as a desktop client for regular payments or as a server utility for merchants and other payment services.

Ysangkok: /* Features */ remove block size discussion not specific to bitcoin core, move network alert to new bullet point

2020-06-30T17:12:12Z

Features: remove block size discussion not specific to bitcoin core, move network alert to new bullet point

← Older revision		Revision as of 17:12, 30 June 2020
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	* Payment requests (BIP 70)		* Payment requests (BIP 70)
	* Coin control		* Coin control
	* Bitcoin Core uses [[OpenTimestamps]] to timestamp merge commits.<ref>{{cite web\|url=https://github.com/bitcoin/bitcoin/blob/ebd786b72a2a15143d7ef4ea2229fef121bd8f12/contrib/devtools/README.md#create-and-verify-timestamps-of-merge-commits\|title=Bitcoin Core devtools README - Create and verify timestamps of merge commits\|date=\|website=GitHub\|archive-url=\|archive-date=\|accessdate=May 5, 2018}}</ref>		* Bitcoin Core uses OpenTimestamps.org to timestamp merge commits.<ref>{{cite web\|url=https://github.com/bitcoin/bitcoin/blob/ebd786b72a2a15143d7ef4ea2229fef121bd8f12/contrib/devtools/README.md#create-and-verify-timestamps-of-merge-commits\|title=Bitcoin Core devtools README - Create and verify timestamps of merge commits\|date=\|website=GitHub\|archive-url=\|archive-date=\|accessdate=May 5, 2018}}</ref>
	* Checkpoints which have been hard coded into the client are used only to prevent Denial of Service attacks against nodes which are initially syncing the chain. For this reason the checkpoints included are only as of several years ago.<ref name="check">{{cite web \|url=https://github.com/bitcoin/bitcoin/blob/master/src/checkpoints.cpp \|title=checkpoints.cpp \|work=Repository source code \|publisher=GitHub, Inc. \|accessdate=13 November 2016 }}</ref><ref>{{cite web \|title=bitcoin/chainparams.cpp \|url=https://github.com/bitcoin/bitcoin/blob/master/src/chainparams.cpp \|website=GitHub \|accessdate=21 October 2018}}</ref>{{failed verification\|date=December 2019}} A one megabyte block size limit was added in 2010 by Satoshi Nakamoto. This limited the maximum network capacity to about three transactions per second.<ref name="leadbit">{{Cite news \|url=https://www.technologyreview.com/s/537486/leaderless-bitcoin-struggles-to-make-its-most-crucial-decision/ \|title=Leaderless Bitcoin Struggles to Make Its Most Crucial Decision \|author=Mike Orcutt \|accessdate=15 November 2016 \|date=19 May 2015 \|work=MIT Technology Review }}</ref> Since then, network capacity has been improved incrementally both through block size increases and improved wallet behavior. A network alert system was included by Satoshi Nakamoto as a way of informing users of important news regarding bitcoin.<ref name="asr">{{cite web \|url=https://bitcoin.org/en/alert/2016-11-01-alert-retirement \|title=Alert System Retirement \|date=1 November 2016 \|publisher=Bitcoin Project \|accessdate=16 November 2016 }}</ref> In November 2016 it was retired. It had become obsolete as news on bitcoin is now widely disseminated.		* Checkpoints which have been hard coded into the client are used only to prevent Denial of Service attacks against nodes which are initially syncing the chain. For this reason the checkpoints included are only as of several years ago.<ref name="check">{{cite web \|url=https://github.com/bitcoin/bitcoin/blob/master/src/checkpoints.cpp \|title=checkpoints.cpp \|work=Repository source code \|publisher=GitHub, Inc. \|accessdate=13 November 2016 }}</ref><ref>{{cite web \|title=bitcoin/chainparams.cpp \|url=https://github.com/bitcoin/bitcoin/blob/master/src/chainparams.cpp \|website=GitHub \|accessdate=21 October 2018}}</ref>
			* A network alert system was included by Satoshi Nakamoto as a way of informing users of important news regarding bitcoin.<ref name="asr">{{cite web \|url=https://bitcoin.org/en/alert/2016-11-01-alert-retirement \|title=Alert System Retirement \|date=1 November 2016 \|publisher=Bitcoin Project \|accessdate=16 November 2016 }}</ref> In November 2016 it was retired. It had become obsolete as news on bitcoin is now widely disseminated.

	== Naming Controversy ==		== Naming Controversy ==

Ysangkok: /* Features */ timestamping, checkpoints (from deleted wikipedia article)

2020-06-30T17:10:42Z

Features: timestamping, checkpoints (from deleted wikipedia article)

← Older revision		Revision as of 17:10, 30 June 2020
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	* Payment requests (BIP 70)		* Payment requests (BIP 70)
	* Coin control		* Coin control
			* Bitcoin Core uses [[OpenTimestamps]] to timestamp merge commits.<ref>{{cite web\|url=https://github.com/bitcoin/bitcoin/blob/ebd786b72a2a15143d7ef4ea2229fef121bd8f12/contrib/devtools/README.md#create-and-verify-timestamps-of-merge-commits\|title=Bitcoin Core devtools README - Create and verify timestamps of merge commits\|date=\|website=GitHub\|archive-url=\|archive-date=\|accessdate=May 5, 2018}}</ref>
			* Checkpoints which have been hard coded into the client are used only to prevent Denial of Service attacks against nodes which are initially syncing the chain. For this reason the checkpoints included are only as of several years ago.<ref name="check">{{cite web \|url=https://github.com/bitcoin/bitcoin/blob/master/src/checkpoints.cpp \|title=checkpoints.cpp \|work=Repository source code \|publisher=GitHub, Inc. \|accessdate=13 November 2016 }}</ref><ref>{{cite web \|title=bitcoin/chainparams.cpp \|url=https://github.com/bitcoin/bitcoin/blob/master/src/chainparams.cpp \|website=GitHub \|accessdate=21 October 2018}}</ref>{{failed verification\|date=December 2019}} A one megabyte block size limit was added in 2010 by Satoshi Nakamoto. This limited the maximum network capacity to about three transactions per second.<ref name="leadbit">{{Cite news \|url=https://www.technologyreview.com/s/537486/leaderless-bitcoin-struggles-to-make-its-most-crucial-decision/ \|title=Leaderless Bitcoin Struggles to Make Its Most Crucial Decision \|author=Mike Orcutt \|accessdate=15 November 2016 \|date=19 May 2015 \|work=MIT Technology Review }}</ref> Since then, network capacity has been improved incrementally both through block size increases and improved wallet behavior. A network alert system was included by Satoshi Nakamoto as a way of informing users of important news regarding bitcoin.<ref name="asr">{{cite web \|url=https://bitcoin.org/en/alert/2016-11-01-alert-retirement \|title=Alert System Retirement \|date=1 November 2016 \|publisher=Bitcoin Project \|accessdate=16 November 2016 }}</ref> In November 2016 it was retired. It had become obsolete as news on bitcoin is now widely disseminated.

	== Naming Controversy ==		== Naming Controversy ==

Ysangkok: add sections "development" and "version history" from deleted wikipedia article

2020-06-30T17:09:16Z

add sections "development" and "version history" from deleted wikipedia article

← Older revision		Revision as of 17:09, 30 June 2020
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	On the other hand, many people are happy with the name Bitcoin Core and continue to use it. As long as it's emphasized that Bitcoin Core is just one possible software implementation of bitcoin that people are free to use or not use.		On the other hand, many people are happy with the name Bitcoin Core and continue to use it. As long as it's emphasized that Bitcoin Core is just one possible software implementation of bitcoin that people are free to use or not use.

			==Development==
			The original creator of the bitcoin client has described their approach to the software's authorship as it being written first to prove to themselves that the concept of purely peer-to-peer electronic cash was valid and that a paper with solutions could be written. The lead developer is Wladimir J. van der Laan, who took over the role on 8 April 2014.<ref name="hunt"/> [[Gavin Andresen]] was the former lead maintainer for the software client. Andresen left the role of lead developer for bitcoin to work on the strategic development of its technology.<ref name="hunt">Bitcoin: The Hunt of Satoshi Nakamoto, Alex Preukschat, Josep Busquet, 2015, Europe Comics, ISBN 9791032800201, page 87 [https://play.google.com/store/books/details?id=438FCwAAQBAJ]</ref> Bitcoin Core developers have been in charge of bitcoin's development since [[Satoshi Nakamoto]] left the project.<ref name="wtbf">{{Cite news \|url=https://www.forbes.com/sites/laurashin/2017/10/23/will-this-battle-for-the-soul-of-bitcoin-destroy-it/#62d19db23d3c \|title=Will This Battle For The Soul Of Bitcoin Destroy It? \|author=Laura Shin \|accessdate=14 April 2018 \|date=23 October 2017 \|work=Forbes }}</ref> Bitcoin Core in 2015 was central to a dispute with [[Bitcoin XT]], a competing client that sought to increase the blocksize.<ref name="NewYorker">{{Cite news \|url=https://www.newyorker.com/business/currency/inside-the-fight-over-bitcoins-future
			\|title=Inside the Fight Over Bitcoin’s Future \|author=Maria Bustillos \|accessdate=29 June 2020 \|date=25 August 2015 \|work=New Yorker}}</ref> Over a dozen different companies and industry groups fund the development of Bitcoin Core.<ref>{{cite web\|url=https://blog.bitmex.com/who-funds-bitcoin-development/\|title=Who Funds Bitcoin Development?\|date=2020-03-28\|publisher=BitMex Research\|access-date=2020-06-30}}</ref>

			[https://www.youtube.com/watch?v=FIt7GLxxIpY Visualization of code changes during 2015]

			==Version history==
			Bitcoin 0.1 was released on 9 January 2009 by Satoshi Nakamoto with only Windows supported. This was followed by some minor bug fixing versions. On 16 December 2009 Bitcoin 0.2 was released. It included a Linux version for the first time and made use of multi-core processors for mining. In version 0.3.2 Nakamoto included checkpoints as a safeguard. After the release of version 0.3.9, Satoshi Nakamoto left the project and shortly after stopped communicating on online forums.

			Between 2011 and 2013 new versions of the software were released at Bitcoin.org.<ref name="abo">{{cite web \|url=https://bitcoin.org/en/about-us#sponsorship \|title=About bitcoin.org \|publisher=Bitcoin Project \|accessdate=14 November 2016 }}</ref> Developers wanted to differentiate themselves as creators of software rather than advocates for bitcoin and so now maintain bitcoincore.org for just the software.

			Bitcoin-Qt version 0.5.0 was released on 1 November 2011. It introduced a front end that uses the Qt user interface toolkit.<ref name="bqt">{{cite web \|url=https://bitcoin.org/en/release/v0.5.0 \|title=Bitcoin-Qt version 0.5.0 released \|date=1 November 2011 \|publisher=Bitcoin Project \|accessdate=13 November 2016 }}</ref> The software previously used Berkeley DB for database management. Developers switched to LevelDB in release 0.8 in order to reduce blockchain synchronization time ([[initial block download]], beware, a misnomer). The update to this release resulted in a minor blockchain fork on the 11 March 2013. The fork was resolved shortly afterwards. Seeding nodes through Internet Relay Chat was discontinued in version 0.8.2. From version 0.9.0 the software was renamed to Bitcoin Core. Transaction fees were reduced again by a factor of ten as a means to encourage microtransactions. Although Bitcoin Core does not use OpenSSL for the operation of the network, the software did use OpenSSL for remote procedure calls. Version 0.9.1 was released to remove the network's vulnerability to the Heartbleed bug.

			Release 0.10 was made public on 16 February 2015. It introduced a consensus library which gave programmers easy access to the rules governing consensus on the network. In version 0.11.2 developers added a new feature which allowed transactions to be made unspendable until a specific time in the future.<ref name="v0.11.2">{{cite web \|url=https://bitcoin.org/en/release/v0.11.2 \|title=Bitcoin Core version 0.11.2 released \|date=13 November 2015 \|publisher=Bitcoin Project \|accessdate=14 November 2016 }}</ref> Bitcoin Core 0.12.1 was released on April 15, 2016 and enabled multiple soft forks to occur concurrently.<ref name="0.12.1rel">{{Cite news \|url=http://www.nasdaq.com/article/bitcoin-core-0121-released-major-step-forward-for-scalability-cm607209 \|title=Bitcoin Core 0.12.1 Released, Major Step Forward for Scalability \|author=Kyle Torpey \|accessdate=7 November 2016 \|date=15 April 2016 \|work=Bitcoin Magazine \|publisher=NASDAQ.com }}</ref> Around 100 contributors worked on Bitcoin Core 0.13.0 which was released on 23 August 2016.

			In July 2016, the CheckSequenceVerify soft fork activated.<ref>Mastering Bitcoin: Programming the Open Blockchain. Quote "BIP-68 and BIP-112 were activated in May 2016 as a soft fork upgrade to the consensus rules."</ref>

			In October 2016, Bitcoin Core’s 0.13.1 release featured the "[[Segwit]]" soft fork that included a scaling improvement aiming to optimize the bitcoin blocksize. The patch which was originally finalised in April, and 35 developers were engaged to deploy it. This release featured Segregated Witness ([[SegWit]]) which aimed to place downward pressure on transaction fees as well as increase the maximum transaction capacity of the network.<ref name="rel13.1">{{cite web \|url=https://bitcoincore.org/en/releases/0.13.1/ \|title=Bitcoin Core 0.13.1 \|publisher=Bitcoin Core \|accessdate=25 October 2016 }}</ref> The 0.13.1 release endured extensive testing and research leading to some delays in its release date. SegWit prevents various forms of transaction malleability.<ref name="swb">{{cite web\|url=https://bitcoincore.org/en/2016/01/26/segwit-benefits/\|title=Segregated Witness Benefits\|last=\|first=\|date=January 26, 2016\|work=Bitcoin Core\|archive-url=\|archive-date=\|accessdate=October 20, 2018}}</ref>

			In September 2018, a Bitcoin Cash developer discovered the vulnerability CVE 2018-17144 in the Bitcoin Core software that could allow an attacker to crash vulnerable Bitcoin Core nodes and exceed the 21 million coin limit.<ref>{{Cite news\|url=https://bitcoincore.org/en/2018/09/20/notice/\|title=CVE-2018-17144 Full Disclosure\|work=Bitcoin Core\|access-date=2018-09-23\|language=en}}</ref>

			==Bitcoin Improvement Proposals==
			A [[Bitcoin Improvement Proposal]] (BIP) is a design document, typically describing a new feature for Bitcoin with a concise technical specification of the feature and the rationale for it. Bitcoin Core implements some of these design documents.

	==See also==		==See also==

JonathanCross: /* Naming Controversy */ Linking UASF

2019-03-03T21:32:39Z

Naming Controversy: Linking UASF

← Older revision		Revision as of 21:32, 3 March 2019
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	Some people like Peter Todd, Luke-jr and Greg Maxwell warned against the renaming to Bitcoin Core because it implied a centralization.<ref>https://www.reddit.com/r/Bitcoin/comments/60jmq2/a_proposal_for_and_demo_of_a_new_bitcoin_address/df73k2h/</ref><ref>https://www.reddit.com/r/Bitcoin/comments/60owl3/did_you_know_that_bitcoin_core_opposed_its_own/</ref><ref>https://bitcoinfoundation.org/forum/index.php?/topic/95-new-name-for-bitcoin-qt-bitcoind/&</ref>.		Some people like Peter Todd, Luke-jr and Greg Maxwell warned against the renaming to Bitcoin Core because it implied a centralization.<ref>https://www.reddit.com/r/Bitcoin/comments/60jmq2/a_proposal_for_and_demo_of_a_new_bitcoin_address/df73k2h/</ref><ref>https://www.reddit.com/r/Bitcoin/comments/60owl3/did_you_know_that_bitcoin_core_opposed_its_own/</ref><ref>https://bitcoinfoundation.org/forum/index.php?/topic/95-new-name-for-bitcoin-qt-bitcoind/&</ref>.

	Bitcoin Core right now may be the most popular or "reference" [[full node]] implementation, but that status depends on the [[economic majority]] continuing to use it<ref>https://bitcoinmagazine.com/articles/a-primer-on-bitcoin-governance-or-why-developers-aren-t-in-charge-of-the-protocol-1473270427/</ref>. Should one day come where another implementation overtakes it economically, that implementation would become the reference implementation. In one situation in 2017 significant parts of the economy moved to the BIP148 UASF implementation<ref>https://bitcoinmagazine.com/articles/long-road-segwit-how-bitcoins-biggest-protocol-upgrade-became-reality/</ref> and then moved back to Core after BIP148 was successful. The point here is that Bitcoin Core does not control bitcoin and the naming "Core" is misleading in that respect.		Bitcoin Core right now may be the most popular or "reference" [[full node]] implementation, but that status depends on the [[economic majority]] continuing to use it<ref>https://bitcoinmagazine.com/articles/a-primer-on-bitcoin-governance-or-why-developers-aren-t-in-charge-of-the-protocol-1473270427/</ref>. Should one day come where another implementation overtakes it economically, that implementation would become the reference implementation. In one situation in 2017 significant parts of the economy moved to the BIP148 [[UASF]] implementation<ref>https://bitcoinmagazine.com/articles/long-road-segwit-how-bitcoins-biggest-protocol-upgrade-became-reality/</ref> and then moved back to Core after BIP148 was successful. The point here is that Bitcoin Core does not control bitcoin and the naming "Core" is misleading in that respect.

	On the other hand, many people are happy with the name Bitcoin Core and continue to use it. As long as it's emphasized that Bitcoin Core is just one possible software implementation of bitcoin that people are free to use or not use.		On the other hand, many people are happy with the name Bitcoin Core and continue to use it. As long as it's emphasized that Bitcoin Core is just one possible software implementation of bitcoin that people are free to use or not use.

Belcher: moved the See Also section higher up

2018-04-23T14:31:57Z

moved the See Also section higher up

@@ Line 31: / Line 31: @@
 On the other hand, many people are happy with the name Bitcoin Core and continue to use it. As long as it's emphasized that Bitcoin Core is just one possible software implementation of bitcoin that people are free to use or not use.
 ==External Links==
@@ Line 43: / Line 50: @@
 <references/>
 [[es:Bitcoin-Qt]]

Belcher: added link to bitcoinmagazine's article on why developers aren’t in charge of the protocol

2018-03-28T15:28:10Z

added link to bitcoinmagazine's article on why developers aren’t in charge of the protocol

← Older revision		Revision as of 15:28, 28 March 2018
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	Some people like Peter Todd, Luke-jr and Greg Maxwell warned against the renaming to Bitcoin Core because it implied a centralization.<ref>https://www.reddit.com/r/Bitcoin/comments/60jmq2/a_proposal_for_and_demo_of_a_new_bitcoin_address/df73k2h/</ref><ref>https://www.reddit.com/r/Bitcoin/comments/60owl3/did_you_know_that_bitcoin_core_opposed_its_own/</ref><ref>https://bitcoinfoundation.org/forum/index.php?/topic/95-new-name-for-bitcoin-qt-bitcoind/&</ref>.		Some people like Peter Todd, Luke-jr and Greg Maxwell warned against the renaming to Bitcoin Core because it implied a centralization.<ref>https://www.reddit.com/r/Bitcoin/comments/60jmq2/a_proposal_for_and_demo_of_a_new_bitcoin_address/df73k2h/</ref><ref>https://www.reddit.com/r/Bitcoin/comments/60owl3/did_you_know_that_bitcoin_core_opposed_its_own/</ref><ref>https://bitcoinfoundation.org/forum/index.php?/topic/95-new-name-for-bitcoin-qt-bitcoind/&</ref>.

	Bitcoin Core right now may be the most popular or "reference" [[full node]] implementation, but that status depends on the [[economic majority]] continuing to use it. Should one day come where another implementation overtakes it economically, that implementation would become the reference implementation. In one situation significant parts of the economy moved to the BIP148 UASF implementation<ref>https://bitcoinmagazine.com/articles/long-road-segwit-how-bitcoins-biggest-protocol-upgrade-became-reality/</ref> and then moved back to Core after BIP148 was successful. The point here is that Bitcoin Core does not control bitcoin and the naming "Core" is misleading in that respect.		Bitcoin Core right now may be the most popular or "reference" [[full node]] implementation, but that status depends on the [[economic majority]] continuing to use it<ref>https://bitcoinmagazine.com/articles/a-primer-on-bitcoin-governance-or-why-developers-aren-t-in-charge-of-the-protocol-1473270427/</ref>. Should one day come where another implementation overtakes it economically, that implementation would become the reference implementation. In one situation in 2017 significant parts of the economy moved to the BIP148 UASF implementation<ref>https://bitcoinmagazine.com/articles/long-road-segwit-how-bitcoins-biggest-protocol-upgrade-became-reality/</ref> and then moved back to Core after BIP148 was successful. The point here is that Bitcoin Core does not control bitcoin and the naming "Core" is misleading in that respect.

	~~Many~~ other people are happy with the name Bitcoin Core and continue to use it. As long as it's emphasized that Bitcoin Core is just one possible software implementation of bitcoin that people are free to use or not use.		On the other hand, many people are happy with the name Bitcoin Core and continue to use it. As long as it's emphasized that Bitcoin Core is just one possible software implementation of bitcoin that people are free to use or not use.

	==External Links==		==External Links==

Luke-jr: /* See also */

2018-03-23T16:17:36Z

Belcher: fixed references heading

2018-03-16T15:50:02Z

fixed references heading

← Older revision		Revision as of 15:50, 16 March 2018
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	* [https://github.com/bitcoin/bitcoin Current GitHub repository shared with bitcoind]		* [https://github.com/bitcoin/bitcoin Current GitHub repository shared with bitcoind]

	~~<references~~		== References ==

	/>		<references/>

	==See also==		==See also==

← Older revision		Revision as of 16:17, 23 March 2018
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	==See also==		==See also==

			* [[bitcoind]]
	* [[Full node]]		* [[Full node]]
			* [[Bitcoin Knots]]
	* [[QBitcoin]]		* [[QBitcoin]]
	* [[bitcoind]]

	[[es:Bitcoin-Qt]]		[[es:Bitcoin-Qt]]

← Older revision		Revision as of 07:50, 26 September 2022
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	* Coin control		* Coin control
	* Bitcoin Core uses OpenTimestamps.org to timestamp merge commits.<ref>{{cite web\|url=https://github.com/bitcoin/bitcoin/blob/ebd786b72a2a15143d7ef4ea2229fef121bd8f12/contrib/devtools/README.md#create-and-verify-timestamps-of-merge-commits\|title=Bitcoin Core devtools README - Create and verify timestamps of merge commits\|date=\|website=GitHub\|archive-url=\|archive-date=\|accessdate=May 5, 2018}}</ref>		* Bitcoin Core uses OpenTimestamps.org to timestamp merge commits.<ref>{{cite web\|url=https://github.com/bitcoin/bitcoin/blob/ebd786b72a2a15143d7ef4ea2229fef121bd8f12/contrib/devtools/README.md#create-and-verify-timestamps-of-merge-commits\|title=Bitcoin Core devtools README - Create and verify timestamps of merge commits\|date=\|website=GitHub\|archive-url=\|archive-date=\|accessdate=May 5, 2018}}</ref>
	* Checkpoints ~~which~~ have been hard coded into the client are used only to prevent Denial of Service attacks against nodes ~~which~~ are initially syncing the chain. For this reason the checkpoints included are only as of several years ago.<ref name="check">{{cite web \|url=https://github.com/bitcoin/bitcoin/blob/master/src/checkpoints.cpp \|title=checkpoints.cpp \|work=Repository source code \|publisher=GitHub, Inc. \|accessdate=13 November 2016 }}</ref><ref>{{cite web \|title=bitcoin/chainparams.cpp \|url=https://github.com/bitcoin/bitcoin/blob/master/src/chainparams.cpp \|website=GitHub \|accessdate=21 October 2018}}</ref>		* Checkpoints that have been hard coded into the client are used only to prevent Denial of Service attacks against nodes that are initially syncing the chain. For this reason, the checkpoints included are only as of several years ago.<ref name="check">{{cite web \|url=https://github.com/bitcoin/bitcoin/blob/master/src/checkpoints.cpp \|title=checkpoints.cpp \|work=Repository source code \|publisher=GitHub, Inc. \|accessdate=13 November 2016 }}</ref><ref>{{cite web \|title=bitcoin/chainparams.cpp \|url=https://github.com/bitcoin/bitcoin/blob/master/src/chainparams.cpp \|website=GitHub \|accessdate=21 October 2018}}</ref>
	* A network alert system was included by Satoshi Nakamoto as a way of informing users of important news regarding bitcoin.<ref name="asr">{{cite web \|url=https://bitcoin.org/en/alert/2016-11-01-alert-retirement \|title=Alert System Retirement \|date=1 November 2016 \|publisher=Bitcoin Project \|accessdate=16 November 2016 }}</ref> In November 2016 it was retired. It had become obsolete as news on bitcoin is now widely disseminated.		* A network alert system was included by Satoshi Nakamoto as a way of informing users of important news regarding bitcoin.<ref name="asr">{{cite web \|url=https://bitcoin.org/en/alert/2016-11-01-alert-retirement \|title=Alert System Retirement \|date=1 November 2016 \|publisher=Bitcoin Project \|accessdate=16 November 2016 }}</ref> In November 2016 it was retired. It had become obsolete as news on bitcoin is now widely disseminated.

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	==Version history==		==Version history==
	Bitcoin 0.1 was released on 9 January 2009 by Satoshi Nakamoto with only Windows supported. This was followed by some minor bug fixing versions. On 16 December 2009 Bitcoin 0.2 was released. It included a Linux version for the first time and made use of multi-core processors for mining. In version 0.3.2 Nakamoto included checkpoints as a safeguard. After the release of version 0.3.9, Satoshi Nakamoto left the project and shortly after stopped communicating on online forums.		Bitcoin 0.1 was released on 9 January 2009 by Satoshi Nakamoto with only Windows supported. This was followed by some minor bug-fixing versions. On 16 December 2009 Bitcoin 0.2 was released. It included a Linux version for the first time and made use of multi-core processors for mining. In version 0.3.2 Nakamoto included checkpoints as a safeguard. After the release of version 0.3.9, Satoshi Nakamoto left the project and shortly after stopped communicating on online forums.

	Between 2011 and 2013 new versions of the software were released at Bitcoin.org.<ref name="abo">{{cite web \|url=https://bitcoin.org/en/about-us#sponsorship \|title=About bitcoin.org \|publisher=Bitcoin Project \|accessdate=14 November 2016 }}</ref> Developers wanted to differentiate themselves as creators of software rather than advocates for bitcoin and so now maintain bitcoincore.org for just the software.		Between 2011 and 2013 new versions of the software were released at Bitcoin.org.<ref name="abo">{{cite web \|url=https://bitcoin.org/en/about-us#sponsorship \|title=About bitcoin.org \|publisher=Bitcoin Project \|accessdate=14 November 2016 }}</ref> Developers wanted to differentiate themselves as creators of software rather than advocates for bitcoin and so now maintain bitcoincore.org for just the software.

	Bitcoin-Qt version 0.5.0 was released on 1 November 2011. It introduced a front end that uses the Qt user interface toolkit.<ref name="bqt">{{cite web \|url=https://bitcoin.org/en/release/v0.5.0 \|title=Bitcoin-Qt version 0.5.0 released \|date=1 November 2011 \|publisher=Bitcoin Project \|accessdate=13 November 2016 }}</ref> The software previously used Berkeley DB for database management. Developers switched to LevelDB in release 0.8 in order to reduce blockchain synchronization time ([[initial block download]], beware, a misnomer). The update to this release resulted in a minor blockchain fork on the 11 March 2013. The fork was resolved shortly ~~afterwards~~. Seeding nodes through Internet Relay Chat was discontinued in version 0.8.2. From version 0.9.0 the software was renamed to Bitcoin Core. Transaction fees were reduced again by a factor of ten as a means to encourage microtransactions. Although Bitcoin Core does not use OpenSSL for the operation of the network, the software did use OpenSSL for remote procedure calls. Version 0.9.1 was released to remove the network's vulnerability to the Heartbleed bug.		Bitcoin-Qt version 0.5.0 was released on 1 November 2011. It introduced a front end that uses the Qt user interface toolkit.<ref name="bqt">{{cite web \|url=https://bitcoin.org/en/release/v0.5.0 \|title=Bitcoin-Qt version 0.5.0 released \|date=1 November 2011 \|publisher=Bitcoin Project \|accessdate=13 November 2016 }}</ref> The software previously used Berkeley DB for database management. Developers switched to LevelDB in release 0.8 in order to reduce blockchain synchronization time ([[initial block download]], beware, a misnomer). The update to this release resulted in a minor blockchain fork on the 11 March 2013. The fork was resolved shortly afterward. Seeding nodes through Internet Relay Chat was discontinued in version 0.8.2. From version 0.9.0 the software was renamed Bitcoin Core. Transaction fees were reduced again by a factor of ten as a means to encourage microtransactions. Although Bitcoin Core does not use OpenSSL for the operation of the network, the software did use OpenSSL for remote procedure calls. Version 0.9.1 was released to remove the network's vulnerability to the Heartbleed bug.

	Release 0.10 was made public on 16 February 2015. It introduced a consensus library which gave programmers easy access to the rules governing consensus on the network. In version 0.11.2 developers added a new feature which allowed transactions to be made unspendable until a specific time in the future.<ref name="v0.11.2">{{cite web \|url=https://bitcoin.org/en/release/v0.11.2 \|title=Bitcoin Core version 0.11.2 released \|date=13 November 2015 \|publisher=Bitcoin Project \|accessdate=14 November 2016 }}</ref> Bitcoin Core 0.12.1 was released on April 15, 2016 and enabled multiple soft forks to occur concurrently.<ref name="0.12.1rel">{{Cite news \|url=http://www.nasdaq.com/article/bitcoin-core-0121-released-major-step-forward-for-scalability-cm607209 \|title=Bitcoin Core 0.12.1 Released, Major Step Forward for Scalability \|author=Kyle Torpey \|accessdate=7 November 2016 \|date=15 April 2016 \|work=Bitcoin Magazine \|publisher=NASDAQ.com }}</ref> Around 100 contributors worked on Bitcoin Core 0.13.0 which was released on 23 August 2016.		Release 0.10 was made public on 16 February 2015. It introduced a consensus library which gave programmers easy access to the rules governing consensus on the network. In version 0.11.2 developers added a new feature which allowed transactions to be made unspendable until a specific time in the future.<ref name="v0.11.2">{{cite web \|url=https://bitcoin.org/en/release/v0.11.2 \|title=Bitcoin Core version 0.11.2 released \|date=13 November 2015 \|publisher=Bitcoin Project \|accessdate=14 November 2016 }}</ref> Bitcoin Core 0.12.1 was released on April 15, 2016 and enabled multiple soft forks to occur concurrently.<ref name="0.12.1rel">{{Cite news \|url=http://www.nasdaq.com/article/bitcoin-core-0121-released-major-step-forward-for-scalability-cm607209 \|title=Bitcoin Core 0.12.1 Released, Major Step Forward for Scalability \|author=Kyle Torpey \|accessdate=7 November 2016 \|date=15 April 2016 \|work=Bitcoin Magazine \|publisher=NASDAQ.com }}</ref> Around 100 contributors worked on Bitcoin Core 0.13.0 which was released on 23 August 2016.

	In July 2016, the CheckSequenceVerify soft fork activated.<ref>Mastering Bitcoin: Programming the Open Blockchain. Quote "BIP-68 and BIP-112 were activated in May 2016 as a soft fork upgrade to the consensus rules."</ref>		In July 2016, the CheckSequenceVerify soft fork was activated.<ref>Mastering Bitcoin: Programming the Open Blockchain. Quote "BIP-68 and BIP-112 were activated in May 2016 as a soft fork upgrade to the consensus rules."</ref>

	In October 2016, Bitcoin Core’s 0.13.1 release featured the "[[Segwit]]" soft fork that included a scaling improvement aiming to optimize the bitcoin ~~blocksize~~. The patch ~~which~~ was originally ~~finalised~~ in April, and 35 developers were engaged to deploy it. This release featured Segregated Witness ([[SegWit]]) which aimed to place downward pressure on transaction fees as well as increase the maximum transaction capacity of the network.<ref name="rel13.1">{{cite web \|url=https://bitcoincore.org/en/releases/0.13.1/ \|title=Bitcoin Core 0.13.1 \|publisher=Bitcoin Core \|accessdate=25 October 2016 }}</ref> The 0.13.1 release endured extensive testing and research leading to some delays in its release date. SegWit prevents various forms of transaction malleability.<ref name="swb">{{cite web\|url=https://bitcoincore.org/en/2016/01/26/segwit-benefits/\|title=Segregated Witness Benefits\|last=\|first=\|date=January 26, 2016\|work=Bitcoin Core\|archive-url=\|archive-date=\|accessdate=October 20, 2018}}</ref>		In October 2016, Bitcoin Core’s 0.13.1 release featured the "[[Segwit]]" soft fork that included a scaling improvement aiming to optimize the bitcoin block size. The patch was originally finalized in April and 35 developers were engaged to deploy it. This release featured Segregated Witness ([[SegWit]]) which aimed to place downward pressure on transaction fees as well as increase the maximum transaction capacity of the network.<ref name="rel13.1">{{cite web \|url=https://bitcoincore.org/en/releases/0.13.1/ \|title=Bitcoin Core 0.13.1 \|publisher=Bitcoin Core \|accessdate=25 October 2016 }}</ref> The 0.13.1 release endured extensive testing and research leading to some delays in its release date. SegWit prevents various forms of transaction malleability.<ref name="swb">{{cite web\|url=https://bitcoincore.org/en/2016/01/26/segwit-benefits/\|title=Segregated Witness Benefits\|last=\|first=\|date=January 26, 2016\|work=Bitcoin Core\|archive-url=\|archive-date=\|accessdate=October 20, 2018}}</ref>

	In September 2018, a Bitcoin Cash developer discovered the vulnerability CVE 2018-17144 in the Bitcoin Core software that could allow an attacker to crash vulnerable Bitcoin Core nodes and exceed the 21 million coin limit.<ref>{{Cite news\|url=https://bitcoincore.org/en/2018/09/20/notice/\|title=CVE-2018-17144 Full Disclosure\|work=Bitcoin Core\|access-date=2018-09-23\|language=en}}</ref>		In September 2018, a Bitcoin Cash developer discovered the vulnerability CVE 2018-17144 in the Bitcoin Core software that could allow an attacker to crash vulnerable Bitcoin Core nodes and exceed the 21 million coin limit.<ref>{{Cite news\|url=https://bitcoincore.org/en/2018/09/20/notice/\|title=CVE-2018-17144 Full Disclosure\|work=Bitcoin Core\|access-date=2018-09-23\|language=en}}</ref>