NotATether: no need to mention the photographer

2026-07-17T09:13:32Z

no need to mention the photographer

← Older revision		Revision as of 09:13, 17 July 2026
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	{{infobox person\|name=Adam Back		{{infobox person\|name=Adam Back
	\|image=[[File:Adam Back 2025.png\|256px]]		\|image=[[File:Adam Back 2025.png\|256px]]
	\|caption=Adam Back in 2025. ~~Photo by Alexandre Sitter~~		\|caption=Adam Back in 2025.
	\|knownfor=[[Hashcash]]; co-founding [[Blockstream]]		\|knownfor=[[Hashcash]]; co-founding [[Blockstream]]
	\|notableworks=[[Hashcash]]; ''Enabling Blockchain Innovations with Pegged Sidechains''		\|notableworks=[[Hashcash]]; ''Enabling Blockchain Innovations with Pegged Sidechains''

NotATether: Expand from stub

2026-07-17T09:13:06Z

Expand from stub

← Older revision		Revision as of 09:13, 17 July 2026
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	{{~~stub~~}}		{{infobox person\|name=Adam Back
			\|image=[[File:Adam Back 2025.png\|256px]]
			\|caption=Adam Back in 2025. Photo by Alexandre Sitter
			\|knownfor=[[Hashcash]]; co-founding [[Blockstream]]
			\|notableworks=[[Hashcash]]; ''Enabling Blockchain Innovations with Pegged Sidechains''
			}}
			'''Adam Back''' is a British computer scientist, cryptographer and cypherpunk who invented [[Hashcash]], a [[proof-of-work]] system announced in 1997 and later cited in the Bitcoin white paper, and co-founded the Bitcoin infrastructure company [[Blockstream]].<ref name="guardian">{{cite web\|url=https://www.theguardian.com/technology/2026/apr/08/british-computer-scientist-adam-back-denies-he-is-bitcoin-developer-satoshi-nakamoto\|title=British computer scientist denies he is bitcoin developer Satoshi Nakamoto\|work=The Guardian\|author=Down, Aisha\|date=8 April 2026\|accessdate=4 July 2026}}</ref><ref name="hashcash-papers">{{cite web\|url=http://www.hashcash.org/papers/\|title=Hashcash papers\|publisher=Hashcash.org\|accessdate=17 July 2026}}</ref><ref name="whitepaper">{{cite web\|url=https://bitcoin.org/bitcoin.pdf\|title=Bitcoin: A Peer-to-Peer Electronic Cash System\|author=Nakamoto, Satoshi\|date=31 October 2008\|accessdate=4 July 2026}}</ref><ref name="blockstream-ceo">{{cite web\|url=https://blockstream.com/press-releases/2016-10-03-blockstream-appoints-hashcash-inventor-dr-adam-back-as-ceo/\|title=Blockstream Appoints Hashcash Inventor Dr. Adam Back as CEO\|publisher=Blockstream\|date=3 October 2016\|accessdate=4 July 2026}}</ref>

	~~Adam~~ Back is a ~~British cryptographer~~ and ~~crypto-hacker notable as~~ the ~~inventor~~ of ~~[[Hashcash]]~~, the ~~[[proof~~-of-~~work]] system used by [[Bitcoin]].~~		==Background and Hashcash==
			Back received a Ph.D. in distributed systems and computer science from the University of Exeter. Before Blockstream, he worked in cryptography, electronic cash and privacy technology and held senior roles at Zero-Knowledge Systems, Microsoft, EMC and VMware; he also co-founded the cloud-infrastructure company Pi Corporation.<ref name="blockstream-ceo" />

	~~He is currently CEO at [[Blockstream]]~~.<ref>http://~~adam3~~.us/~~about~~/</ref> ~~Other employees at Blockstream have included [[Pieter Wuille]], [[Gregory Sanders]], [[Matt Corallo]], [[Mark Friedenbach]], [[Jorge Timón]].~~		Back first announced Hashcash on the cypherpunks mailing list in March 1997. It was designed to deter email spam and denial-of-service attacks by requiring a sender to calculate a proof-of-work stamp that was moderately costly to produce but inexpensive for a recipient to verify. Back described the system formally in his 2002 paper ''Hashcash - A Denial of Service Counter-Measure''.<ref name="hashcash-papers" /><ref name="hashcash-paper">{{cite web\|url=http://www.hashcash.org/papers/hashcash.pdf\|title=Hashcash - A Denial of Service Counter-Measure\|author=Back, Adam\|date=1 August 2002\|accessdate=17 July 2026}}</ref>

	Back was an opponent of [[SegWit2x]].<ref>[https://twitter.com/adam3us/status/913495697936277504 Tweet by Adam Back (adam3us) saying ''segwit2x is very likely to degrade into "paypal2.0" permissioned bank. ~~those unaware~~ of ~~history/too stubborn~~ to ~~learn, are doomed to repeat.'~~'~~]</ref><ref>[https~~:~~//www.reddit.com/r/Bitcoin/comments/72ryef/it_is_time_to_call_off_nyasegwit2x_and_work/ Adam Back (adam3us) post on Reddit: ''It is time to call off NYA/segwit2x~~ and work ~~together to scale Bitcoin to compete against Fiat~~. ~~Please.'']~~</~~ref~~>		Bitcoin adapted this computational asymmetry for a different purpose. The white paper describes a proof-of-work system similar to Hashcash for Bitcoin's distributed timestamp server: miners repeatedly hash block headers until one satisfies the network target, and the accumulated work helps establish transaction order, resist double-spending and secure the issuance of new coins.<ref name="whitepaper" />

	== ~~See~~ also ==		==Correspondence with Satoshi Nakamoto==
	* https://en.~~wikipedia~~.~~org~~/~~wiki~~/~~Adam_Back~~		On 20 August 2008, [[Satoshi Nakamoto]] emailed Back a pre-release draft then titled ''Electronic Cash Without a Trusted Third Party'' and asked him to verify the citation to the Hashcash paper. Back confirmed the citation on 21 August and pointed Satoshi to Wei Dai's [[b-money]] proposal. Satoshi replied that he had not previously seen the b-money page and then contacted Dai to establish its publication date. The b-money citation became the first reference in the published Bitcoin white paper, while Hashcash appeared as the sixth.<ref name="back-statement">{{cite web\|url=https://bitcoindefense.org/assets/documents/First-Witness-Statement-of-Dr-Adam-Back.pdf\|title=First Witness Statement of Dr Adam Back\|author=Back, Adam\|date=17 July 2023\|publisher=High Court of Justice\|accessdate=17 July 2026}}</ref><ref name="copa-judgment">{{cite web\|url=https://www.judiciary.uk/wp-content/uploads/2024/05/COPA-v-Wright-Judgment.pdf\|title=Crypto Open Patent Alliance v Craig Steven Wright: Approved Judgment\|author=Mellor, James\|publisher=High Court of Justice of England and Wales\|date=20 May 2024\|accessdate=17 July 2026}}</ref>

			Back later suggested that Satoshi also examine MicroMint, another micropayment proposal. Their next documented contact was on 10 January 2009, when Satoshi informed Back that the Bitcoin software had been released.<ref name="back-statement" />

			The correspondence was made public when Back gave evidence in the 2024 [[wikipedia:Crypto Open Patent Alliance\|Crypto Open Patent Alliance]] case concerning Craig Wright's claim to be Satoshi. The High Court judgment described Back's evidence as careful, considered and truthful, and found that the emails contradicted Wright's account of Bitcoin's development.<ref name="copa-judgment" />

			==Blockstream and sidechains==
			In October 2014, Back was one of nine authors of ''Enabling Blockchain Innovations with Pegged Sidechains''. The paper proposed two-way pegs that would allow bitcoins and other ledger assets to move between separate blockchains, enabling experimentation while attempting to isolate failures from the Bitcoin main chain.<ref name="sidechains">{{cite web\|url=https://blockstream.com/sidechains.pdf\|title=Enabling Blockchain Innovations with Pegged Sidechains\|author=Back, Adam et al.\|date=22 October 2014\|publisher=Blockstream\|accessdate=17 July 2026}}</ref>

			In 2014, Back was one of Blockstream's 11 co-founders. The company initially focused on sidechains and other protocol-level extensions to Bitcoin and announced a US$21 million seed round in November 2014.<ref name="seed-round">{{cite web\|url=https://blog.blockstream.com/en-blockstream-closes-21m-seed-round/\|title=Blockstream closes $21M seed round\|publisher=Blockstream\|date=17 November 2014\|accessdate=17 July 2026}}</ref> Back served as president and chief operating officer before Blockstream appointed him CEO on 3 October 2016.<ref name="blockstream-ceo" />

			In a 2014 statement, Back said Blockstream would support decentralisation, end-to-end security, user control and permissionless innovation, and described sidechains as the company's most pressing technical work.<ref>{{cite web\|url=https://blog.blockstream.com/en-blockstream-a-champion-of-bitcoins-core-values/\|title=Blockstream: A Champion of Bitcoin's Core Values\|author=Back, Adam\|publisher=Blockstream\|date=17 November 2014\|accessdate=17 July 2026}}</ref> During the 2017 scaling dispute, he publicly opposed the [[SegWit2x]] hard-fork proposal.<ref>[https://x.com/adam3us/status/913495697936277504 Adam Back on X], 28 September 2017.</ref><ref>[https://old.reddit.com/r/Bitcoin/comments/72ryef/it_is_time_to_call_off_nyasegwit2x_and_work/ “It is time to call off NYA/segwit2x”], Reddit, 27 September 2017.</ref>

			==Satoshi identity speculation==
			In April 2026, ''The New York Times'' published an investigation claiming that Back was the person behind the Satoshi Nakamoto pseudonym. Back denied being Satoshi and said the similarities cited by the investigation were coincidences among people with similar experience and interests.<ref name="guardian" />

			==See also==
			* [[wikipedia:Adam Back\|Adam Back on Wikipedia]]

	==References==		==References==
	<references />		<references />

Ysangkok: add some links to segwit2x resistance

2021-03-01T22:16:15Z

add some links to segwit2x resistance

← Older revision		Revision as of 22:16, 1 March 2021
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	Adam Back is a British cryptographer and crypto-hacker notable as the inventor of [[Hashcash]], the [[proof-of-work]] system used by [[Bitcoin]].		Adam Back is a British cryptographer and crypto-hacker notable as the inventor of [[Hashcash]], the [[proof-of-work]] system used by [[Bitcoin]].

	He is currently ~~a lead developer~~ at [[Blockstream]].		He is currently CEO at [[Blockstream]].<ref>http://adam3.us/about/</ref> Other employees at Blockstream have included [[Pieter Wuille]], [[Gregory Sanders]], [[Matt Corallo]], [[Mark Friedenbach]], [[Jorge Timón]].

			Back was an opponent of [[SegWit2x]].<ref>[https://twitter.com/adam3us/status/913495697936277504 Tweet by Adam Back (adam3us) saying ''segwit2x is very likely to degrade into "paypal2.0" permissioned bank. those unaware of history/too stubborn to learn, are doomed to repeat.'']</ref><ref>[https://www.reddit.com/r/Bitcoin/comments/72ryef/it_is_time_to_call_off_nyasegwit2x_and_work/ Adam Back (adam3us) post on Reddit: ''It is time to call off NYA/segwit2x and work together to scale Bitcoin to compete against Fiat. Please.'']</ref>

	== See also ==		== See also ==
	* https://en.wikipedia.org/wiki/Adam_Back		* https://en.wikipedia.org/wiki/Adam_Back

			==References==
			<references />

FaceFace: Not much of an improvement, but gotta get the ball rolling right?

2020-01-17T08:47:25Z

Not much of an improvement, but gotta get the ball rolling right?

← Older revision		Revision as of 08:47, 17 January 2020
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	Adam Back is a British cryptographer and crypto-hacker notable as the inventor of [[Hashcash]], the [[proof-of-work]] system used by [[Bitcoin]].		Adam Back is a British cryptographer and crypto-hacker notable as the inventor of [[Hashcash]], the [[proof-of-work]] system used by [[Bitcoin]].

			He is currently a lead developer at [[Blockstream]].

	== See also ==		== See also ==
	* https://en.wikipedia.org/wiki/Adam_Back		* https://en.wikipedia.org/wiki/Adam_Back

JonathanCross: Initial Stub article for Adam Back

2016-01-29T16:43:31Z

Initial Stub article for Adam Back

New page

{{stub}}

Adam Back is a British cryptographer and crypto-hacker notable as the inventor of [[Hashcash]], the [[proof-of-work]] system used by [[Bitcoin]].

== See also ==
* https://en.wikipedia.org/wiki/Adam_Back

Adam Back - Revision history

NotATether: no need to mention the photographer

NotATether: Expand from stub

Ysangkok: add some links to segwit2x resistance

FaceFace: Not much of an improvement, but gotta get the ball rolling right?

JonathanCross: Initial Stub article for Adam Back