Adam Back

Adam Back recalled that he began a PhD at the University of ExeterUniversity of ExeterThe University of Exeter is a research university in Exeter, England, United Kingdom, with campuses in Exeter and Cornwall. It traces its roots to a School of Art founded in Exeter in 1855, became a university under a royal charter in 1955 and joined the Russell Group in 2012.Open the full entry in 1991; the university had a distributed systems group with some parallel hardware, and the challenge of programming such hardware was the topic of his PhD, which was initially more about distributed systems. During the PhD he read Leslie Lamport’s paper on the Byzantine Generals Problem and read all kinds of applied cryptography papers. He said that PGP caught his interest when it came out and that, from that interest, he joined a mailing list of people interested in such technology.⁠[1]

Blockstream’s 2016 announcement states that he holds a PhD in distributed systems and computer science from the University of Exeter; The Block’s profile page describes his doctoral research as covering distributed systems and cryptographic security.⁠[2][3]

A 2026 article in The Block describes him as a vocal participant on the cypherpunk mailing lists from 1995; a 2020 CointelegraphCointelegraphCointelegraph is a digital news outlet covering blockchain, digital assets, artificial intelligence, and fintech, known for its cartoon-style news illustrations. It also runs businesses including Cointelegraph Magazine, research, an accelerator, and events.Open the full entry article states that he made more than 700 posts on the Cypherpunks list. He said that he was in Europe at the time and attended only one of the in-person cypherpunk meetings in the San Francisco Bay Area.⁠[4][5]

He recalled writing an e-cash library that implemented the online version of David ChaumDavid ChaumDavid Chaum is a cryptographer who introduced mix networks, blind signatures and the electronic cash system eCash, initiated the International Association for Cryptologic Research (IACR) and founded DigiCash in Amsterdam; he later developed voter-verifiable voting systems and leads the blockchain project xx network.Open the full entry’s e-cash protocol and another related system of the same kind; he also made and sold some T-shirts printed with an RSA program (about three lines of code, he said) as a protest against United StatesUnited StatesThe United States is a federal country in North America made up of 50 states, the District of Columbia as the seat of government, and territories such as Puerto Rico and Guam; its capital is Washington, D.C. The Continental Congress adopted the Declaration of Independence on July 4, 1776. The 2020 census (April 1, 2020) counted a resident population of 331,449,281, and the 435 seats of the House of Representatives are apportioned among the states on the basis of the census.Open the full entry export controls on cryptography, at a time when he was living in the UK.⁠[1]

He said that he was running a remailer, a service for sending anonymous email, and later ran a Mixmaster remailer for a few years.⁠[1]

Blockstream’s glossary states that in 1997 he proposed Hashcash, a proof-of-work mechanism intended to stop spam and denial-of-service attacks, which is now used as the basis of Bitcoin’s mining algorithm; the glossary names “Hashcash - A Denial of Service Counter-Measure” as his formal paper on Hashcash. In a 2020 interview he called Hashcash his 1997 contribution.⁠[6][5]

He recalled that, while he was running remailers, people had taken it upon themselves to spam through the systems, and it occurred to him that there should be a way to combat the spam problem, which led to Hashcash; he was not aware of Dwork’s paper until somebody sent him a link to it a couple of months after he had posted the source code for Hashcash.⁠[1]

Blockstream’s 2014 seed-round announcement is written in the first person by one of the co-founders, who states that after reading his Hashcash paper in the late 1990s the writer recruited him to join the team of cryptographers at Zero-Knowledge Systems.⁠[7]

In an interview published in January 2020 he said that in August (or July) 2008 he received an email from Satoshi NakamotoSatoshi NakamotoSatoshi Nakamoto is the pseudonymous creator of Bitcoin, who published the Bitcoin white paper in 2008, released the first Bitcoin software and launched the blockchain in 2009, and stopped public activity around 2011; the person’s true identity has never been confirmed.Open the full entry with an e-cash white paper. Trial material made public by the Crypto Open Patent Alliance (COPA) in 2024 shows that on August 20, 2008, Satoshi Nakamoto emailed him to ask him to review a citation of his earlier work in the white paper; he replied that the citation was correct and pointed Satoshi Nakamoto to other resources, including Wei DaiWei DaiWei Dai is a computer engineer and the original author of the open-source cryptography library Crypto++. In 1998 he proposed b-money, a scheme for anonymous digital money that the Bitcoin paper lists as its first reference, and the smallest unit of ether, the wei, is named after him. He also writes on LessWrong about decision theory and AI safety, and proposed the decision theory that came to be called Updateless Decision Theory.Open the full entry’s b-money.⁠[5][8]

A 2024 Decrypt article states that Satoshi Nakamoto sent him a pre-release draft of the Bitcoin white paper for feedback and said he could share it with others, and that he pointed Satoshi Nakamoto to papers on b-money and Micromint. A Bitcoin.com News article states that he noted the resemblance between the concept and b-money, that Satoshi Nakamoto agreed and cited Wei Dai in the white paper, and that he shared a document titled “micromint” and heard nothing more until the Bitcoin software was released.⁠[9][10]

Section 4, “Proof-of-Work,” of the Bitcoin white paper “Bitcoin: A Peer-to-Peer Electronic Cash System” states that implementing a distributed timestamp server on a peer-to-peer basis requires a proof-of-work system “similar to Adam Back’s Hashcash”; reference 6 is his “Hashcash - a denial of service counter-measure” (2002) and reference 1 is Wei Dai’s “b-money” (1998).⁠[11]

A 2020 Decrypt article states that he moved to Malta in 2009.⁠[12]

The Decrypt article states that in the final email Satoshi Nakamoto thanked him for the suggested papers and announced that the open-source Bitcoin software had been released; the email describes the main idea of the system as the generation of a chain of hash-based proof-of-work to create self-evident proof of the majority consensus, with users getting new coins by contributing proof-of-work to the chain.⁠[9]

In the interview published in January 2020 he said that Satoshi Nakamoto sent him the software before the official release but that he did not start running it at the very beginning, and that it seemed to him that Bitcoin had serious privacy limitations compared with David Chaum’s 1981 protocol. He said: “I didn’t help to create Bitcoin, I didn’t program anything nor participate in any programming task.” He also said: “I’ve never revealed my emails to Satoshi and maybe I never will.”⁠[5]

In the interview published in January 2020 he said that he later proposed confidential transactions and Schnorr signatures, and that they proposed the creation of sidechains, such as Liquid, in 2013.⁠[5]

The writer of Blockstream’s seed-round announcement states that in December 2013 he flew to Montreal to recruit the writer to a vision for the future of blockchain and digital assets; that at the start of 2014 the writer flew to Malta to spend a week with him mapping out the ecosystem and future they wanted to see built, where he laid out his vision for Bitcoin and blockchain technology at a whiteboard and the first thing they wrote on it was “Can’t be evil”; and that over the following six months he brought together a group of people to think about the second wave of cryptocurrencies, with the team renting a number of Airbnb houses in Silicon Valley to live and work together and validate that what they thought possible was doable.⁠[7]

On November 17, 2014, Blockstream announced that it had closed a $21 million seed round with nearly 40 investors, led by Reid HoffmanReid HoffmanReid Hoffman is an American entrepreneur, venture investor, author and podcast host, co-founder of LinkedIn, Inflection AI and Manas AI, and a partner at Greylock. A former PayPal executive, he has built and backed businesses in professional networking, artificial intelligence and drug discovery. His co-authored books include The Startup of You and Blitzscaling.Open the full entry, Khosla VenturesKhosla VenturesKhosla Ventures (KV) is an American venture capital firm founded in 2004 by Vinod Khosla, the founding CEO of Sun Microsystems, and headquartered in Menlo Park, California. It made heavy early bets on clean technology, became OpenAI’s first venture capital investor in 2019, and its portfolio also includes companies such as DoorDash, Block (formerly Square), Impossible Foods, and Rocket Lab.Open the full entry and Real Ventures, with other investors including Nicolas Berggruen, Crypto Currency Partners, Future\Perfect Ventures, Danny Hillis, Eric SchmidtEric SchmidtEric Schmidt is a technologist, entrepreneur and philanthropist who was Google’s chief executive officer from 2001 to 2011 and later executive chairman of Alphabet; he chaired the U.S. National Security Commission on Artificial Intelligence and has led the rocket company Relativity Space since 2025.Open the full entry’s Innovation Endeavors, Max LevchinMax LevchinMax Levchin is an entrepreneur and computer scientist, one of the co-founders of PayPal and the founder and chief executive officer of the consumer payments and credit company Affirm.Open the full entry, Mosaic Ventures, Ray Ozzie, Ribbit CapitalRibbit CapitalRibbit Capital is a venture-capital firm founded in 2012 by Meyer “Micky” Malka and headquartered in Palo Alto, California. It began with financial-technology investing and has expanded into AI, commerce and related infrastructure. Its investments include Coinbase, Robinhood and Nubank.Open the full entry and Jerry YangJerry YangJerry Yang is a Yahoo co-founder and former CEO and the founding partner of AME Cloud Ventures. He helped develop Yahoo’s relationships with Yahoo Japan and Alibaba and served as chair of Stanford University’s Board of Trustees.Open the full entry’s AME Cloud Ventures. Among the 11 co-founders listed in the announcement, he is introduced as the inventor of the Hashcash algorithm; the other co-founders it names are Greg Maxwell, Pieter Wuille, Matt Corallo, Mark Friedenbach, Jorge Timon, Jonathan Wilkins, Alex Fowler, Erik Svenson and Francesca Hall.⁠[7]

On October 3, 2016, Blockstream announced the appointment of its co-founder Adam Back as chief executive; in the announcement he said he was “honored to take on the CEO position.” The announcement states that he has worked with Bitcoin’s user, academic, technical, investor and business communities in North America, Asia and Europe, that he is one of the principal sponsors of the Scaling Bitcoin workshops (described there as the first event to bring together the technical community working on Bitcoin), and that he advises several cryptocurrency and Bitcoin startups.⁠[2]

On August 18, 2020, Laura ShinLaura ShinLaura Shin is a cryptocurrency journalist, podcast host and author, a former senior editor at Forbes who founded the crypto media outlet Unchained, hosts its podcast of the same name, and wrote “The Cryptopians,” about the first big cryptocurrency craze.Open the full entry’s podcast Unchained published episode 186, with David Chaum and Adam Back as guests, covering the crypto wars in the United States in the 1990s, the rise and collapse of DigiCashDigiCashDigiCash was an electronic cash company founded in Amsterdam by the cryptographer David Chaum. It developed eCash, a payment system that used blind signatures to protect payers’ privacy, and licensed it to banks in several countries for trials; it moved its headquarters to Silicon Valley in 1997, filed for bankruptcy protection in November 1998, and its software and patents later passed to eCash Technologies.Open the full entry, the development of Hashcash, the two men’s first reactions to Bitcoin and the outlook for Bitcoin’s price.⁠[1]

On August 24, 2021, Blockstream announced a $210 million Series B at a $3.2 billion valuation, led by Baillie GiffordBaillie GiffordBaillie Gifford is an investment management firm headquartered in Edinburgh, Scotland, with a history dating to 1908. It is owned and operated by its working partners. Its businesses cover equities, fixed income, multi-asset and private growth investments, with a focus on holding growth companies for the long term.Open the full entry and iFinex, the operator of Bitfinex, with Baillie Gifford investment manager Allen Farrington joining as a board observer; the funds were to accelerate its Bitcoin mining efforts, acquire Spondoolies to launch an enterprise-grade miner, scale the Liquid Network, which the announcement calls “Bitcoin’s first and most robust sidechain,” and expand the team across all departments.⁠[13]

In February 2024 he testified as a witness at the High Court in the United Kingdom in the case brought by the Crypto Open Patent Alliance against Craig Wright; his 2008 and 2009 emails with Satoshi Nakamoto were entered into the court record during his questioning, and COPA then shared them with the press. A Bitcoin.com News article states that he disclosed the emails at the request of the Bird & Bird legal team.⁠[9][10]

COPA’s statement describes him as the inventor of the proof-of-work system cited in the Bitcoin white paper and says his testimony addressed Craig Wright’s account of who influenced Satoshi Nakamoto; COPA argued that if Satoshi Nakamoto had not previously known of Wei Dai’s b-money, it would be hard to say Satoshi had been significantly influenced by it, contradicting Wright’s claim that his thinking was profoundly influenced by Wei Dai. Mr Justice Mellor of the High Court announced on March 14, 2024, at the conclusion of argument, that Craig Wright was not Satoshi Nakamoto, and handed down his reasons on May 20, 2024 ([2024] EWHC 1198 (Ch)); the court’s July 2024 judgment refers to its findings there that Wright had “lied to the Court repeatedly and extensively.” On December 20, 2024, the court sentenced Wright to 12 months’ imprisonment, suspended for two years, for contempt of court in breaching an order dated July 16, 2024.⁠[8][14][15]

On July 17, 2025, Bitcoin Standard Treasury Company (BSTR) announced that it would go public through a business combination with Cantor Equity Partners I, Inc. (NasdaqNasdaqNasdaq is an exchange operator and financial technology company headquartered in New York. It runs The Nasdaq Stock Market and other markets and provides capital markets technology, regulatory technology, and data and index services. Founded in 1971, it combined with OMX AB in 2008, and in March 2026 the U.S. Securities and Exchange Commission approved its rules for trading tokenized securities.Open the full entry: CEPO), a special purpose acquisition company sponsored by an affiliate of Cantor FitzgeraldCantor FitzgeraldCantor Fitzgerald is a New York-based financial services group that includes the investment bank and primary dealer Cantor Fitzgerald & Co. and controls the brokerage and financial technology company BGC Group and the commercial real estate services company Newmark Group; it lost 658 employees in the September 11, 2001 attacks, has been run since 2025 by Brandon Lutnick, son of Howard Lutnick, and has faced questions from members of Congress over its role as custodian of the reserves of the stablecoin issuer Tether and its stake in Tether.Open the full entry, with Adam Back as chief executive and Sean Bill as chief investment officer. The announcement states that BSTR would launch with 30,021 bitcoin: 25,000 from founding shareholders, whose contribution was advised by Blockstream Capital Partners, an investment manager led by Back together with other long-time Bitcoiners, and 5,021 contributed through an in-kind PIPE, both at $10.00 per share; it says this would make BSTR the fourth-largest public corporate Bitcoin treasury.⁠[16]

The announcement states that the deal also included up to $1.5 billion of fiat PIPE financing: $400 million of common equity committed at announcement at $10.00 per share, up to $750 million of convertible senior notes ($500 million committed) with a $13.00 conversion price, and up to $350 million of convertible preferred stock ($30 million committed) with a $13.00 common-equivalent conversion price, while CEPO would contribute up to about $200 million, subject to CEPO shareholder redemptions, priced at $10.00 per share; the combined company was expected to trade as BSTR, with closing expected in the fourth quarter of 2025. He said in the announcement: “Bitcoin was created as sound money and BSTR is being created to bring that same integrity to modern capital markets.”⁠[16]

On January 30, 2026, a batch of files released by the U.S. Department of Justice under the Epstein Files Transparency Act mentioned Blockstream. DL News states that the files show that Jeffrey Epstein invested in Blockstream in 2014; that emails suggest he and his co-founder Austin Hill were scheduled to visit Epstein in St. Thomas, U.S. Virgin Islands, from April 17 to 20, 2014, with some emails suggesting the meeting may have taken place at or near Little Saint James, Epstein’s private island; that on April 19, 2014, Epstein wrote to the Bitcoin developer Amir Taaki that he had “Andy Back” on his island that weekend; and that it is not clear from the emails whether Epstein was referring to Back in that email or whether Back actually visited the island. The Block states that he and Austin Hill appear in travel booking confirmations for St. Thomas.⁠[17][18]

The Block states that in a July 2014 email to Joi Ito and Epstein, on which Back was copied, Austin Hill wrote that they were “down to the wire” on closing the round, that the $18 million seed round was ten times oversubscribed and that “Reid” had at the last minute asked them to raise the allocation from $50,000 to $500,000. DL News states that a few weeks later Hill wrote that the other co-founders wanted to reduce or remove that allocation because of Epstein’s investment in StellarStellarStellar is an open payment and asset-issuance network launched by Jed McCaleb and Joyce Kim in July 2014. Its native asset is the lumen (XLM). Using the Stellar Consensus Protocol's federated Byzantine agreement model, it connects financial institutions, anchors, stablecoins and cross-border payments. Soroban smart contracts were introduced in 2024.Open the full entry; that in November 2014 Vincenzo Iozzo asked Epstein what he thought of Back and Epstein replied that he liked him; and that in May 2015 Ito proposed a meeting with Back and others to discuss “money and the future of finance,” to which Epstein agreed, without its being clear whether the meeting took place.⁠[18][17]

On February 1, 2026, he posted on X that Blockstream’s founders were introduced to Joi Ito during the company’s 2014 seed-round roadshow and subsequently met Epstein, who was described at the time as a limited partner in Ito’s fund; the fund took a minority stake in Blockstream and sold its shares a couple of months later over a “potential conflict of interest, and other concerns.” He wrote: “Blockstream has no direct nor indirect financial connection with Jeffrey Epstein, or his estate.” The statement did not address the emails about the St. Thomas trip; Austin Hill reposted it. The Block notes that the presence of a name in the files does not, by itself, indicate wrongdoing; DL News states that none of the documents it reviewed suggest wrongdoing by Back or Hill.⁠[18][17]

On February 3, 2026, the Bitcoin developer Luke Dashjr posted on X calling on Back to resign from all positions of authority and to apologize to those he had misled; Dashjr said that he was an initial Blockstream contributor, that Back had promised to list him as a co-founder and treat him the same as the others but “broke that promise” and cut him out, and that he was never involved in Blockstream’s fundraising. Decrypt states that Back and Blockstream did not respond to its request for comment on the files.⁠[19][17]

An article in The Block of May 11, 2026, states that the French bitcoin treasury company Capital B (formerly The Blockchain Group, renamed in July 2025) was raising €15.2 million (about $17.8 million) in a private placement of 23 million ABSA shares at €0.66 each, each with four warrants attached; he took part through Blockstream Capital Partners, which he advises, whose stake would fall from 15.63% to 14.42%, while he himself was set to hold 13.43% on an ordinary basis; the French asset manager TOBAM also took part and would hold 4.20%.⁠[20]

On July 8, 2026, Cantor Equity Partners I and BSTR Holdings announced that they would not proceed under the merger agreement signed in 2025 and would instead pursue amended terms reflecting current market conditions, saying they would provide further details in due course and disclosing no new terms or timetable; the shareholder meeting that had been scheduled for that Friday to consider the merger was postponed indefinitely. BloombergBloomberg L.P.Bloomberg L.P. is a global financial technology, data and media company founded by Michael Bloomberg in 1981. It began by providing terminal services that deliver data, analytics and news to financial professionals, and launched Bloomberg News in 1990. Michael Bloomberg has pledged the vast majority of the company’s profits to his philanthropic organization, Bloomberg Philanthropies.Open the full entry links the change to a tougher crypto market that is challenging Bitcoin treasury companies.⁠[21][22]

An article in The Block of September 2, 2026, states that Capital B had raised €7.6 million ($8.8 million) from him in a private placement of 13.18 million shares at €0.58 each, a 15.4% premium to the September 1 closing price, each with four five-year warrants attached (two exercisable at €0.75, one at €0.98 and one at €1.27); his stake on an ordinary basis would rise from 14.82% to 17.77%, and could reach 27.8% if all the placement warrants were exercised. The article states that the proceeds, together with ongoing operations, could fund 376 more bitcoin, raising Capital B’s potential holdings from 3,145 to 3,521 BTC.⁠[23]

Blockstream’s 2016 announcement states that he has worked at MicrosoftMicrosoftMicrosoft is a technology company founded by Bill Gates and Paul Allen in 1975 and headquartered in Redmond, Washington, with businesses spanning Windows, Microsoft 365, Azure, enterprise software, artificial intelligence, gaming and devices.Open the full entry, EMC, PI, VMware and Zero-Knowledge Systems and has advised many companies on cryptography and e-cash; he co-founded Pi Corporation, a cloud infrastructure provider that was later acquired by EMC, where he became chief security officer of its consumer division. His speaker biography for Bitcoin Asia 2025 describes a two-decade-long vocation as an applied cryptographer and security architect, with senior roles at a number of technology companies including Microsoft, EMC, PI and VMware.⁠[2][24]

A 2020 Decrypt article states that he was born in London and that he can code in C++.⁠[12]

On May 11, 2020, the YouTuber Barely Sociable posted a video titled “Bitcoin - Unmasking Satoshi Nakamoto” arguing that Adam Back is Satoshi Nakamoto on the grounds of similarities in writing style and coding ability, a timeline of the two men’s appearances and disappearances online, his early involvement in the cypherpunk community with e-cash and b-money, and the fact that, of Satoshi Nakamoto’s correspondence with cypherpunks, only his had not been made public; Decrypt states that he said he had deleted his correspondence with Satoshi to protect Satoshi’s identity. Answering Decrypt, he said: “Just that people speculate, but I’m not Satoshi.” On Twitter he wrote “I am not Satoshi despite recent video / reddit claiming so,” and, acknowledging that the timing might look suspicious, called it “Pure coincidence, though.”⁠[12]

The 2020 Decrypt article also states that Craig Wright, who claims to be Satoshi Nakamoto, had sued Back and others who said Wright is not Satoshi. A 2026 Decrypt article states that before his death in 2021 John McAfee said that Back was Satoshi Nakamoto, pointing to shared writing habits such as using two spaces at the beginning of a sentence and British spelling.⁠[12][25]

A 2026 article in The Block states that the HBO documentary “Money Electric: The Bitcoin Mystery,” broadcast in October 2024, pointed to the Canadian developer Peter Todd, who denied it on X; in one scene, when the filmmaker raised his name as a possible Satoshi while he sat on a park bench in Riga, Latvia, he tensed, and in the film he denied being Satoshi and asked that the conversation be kept off the record. The Block’s profile page states that he has consistently denied being Satoshi Nakamoto and has suggested that it might be better for Bitcoin if the creator’s identity remains a mystery.⁠[4][3]

On April 8, 2026, The New York TimesThe New York TimesThe New York Times is an American morning daily newspaper published in New York City. Founded in 1851, it is published by The New York Times Company.Open the full entry published an investigation by John Carreyrou naming him as the prime suspect for Satoshi Nakamoto. The Block states that Carreyrou said he spent a year on it, starting from the scene in the HBO documentary; that he used a database of 134,308 cypherpunk mailing-list posts to narrow 620 early cryptographic mailing-list users down to one suspect by writing traits such as hyphenation errors and spelling variations; and that the report says he outlined all five core features of Bitcoin in 1997 cypherpunk posts, anticipated elements of the solution to the Byzantine Generals Problem and proposed using Hashcash to mint Wei Dai’s b-money coins. The Block writes that the report stops short of declaring him the inventor of Bitcoin and that he did not respond to two requests from Carreyrou for the metadata of emails he produced in the Craig Wright case. Decrypt states instead that Carreyrou’s 18-month investigation concluded that he is Satoshi, relying partly on in-person interviews with him in El Salvador.⁠[4][25]

The same day he posted on X: “I am not Satoshi.” He described the article as a mix of coincidence and similar phrasing from people with similar experience and interests. On Carreyrou’s point that Satoshi described himself as “better with code than words” and that he had replied in the interview that he had done a lot of talking on mailing lists, he explained on X that this referred to being talkative on the Bitcoin development mailing list, and suggested that Carreyrou may be showing confirmation bias. Teddy Fusaro, president of Bitwise, mocked the claim by pointing to his Bitcoin treasury firm with Cantor Fitzgerald.⁠[25]

An article in The Block of January 29, 2026, states that in response to Chamath PalihapitiyaChamath PalihapitiyaChamath Palihapitiya is an investor and business operator who founded and leads Social Capital, and is also co-founder and CEO of the AI software company 8090 and a co-host of the All-In podcast. He previously ran user growth at Facebook and took part in taking several companies public through the Social Capital Hedosophia series of special purpose acquisition companies; he is also an early investor in and director of Beast Industries.Open the full entry, who had posted in November 2025 that quantum threats could emerge within two to five years, he said the risk was more likely “20 to 40 years away, if then.”⁠[26]

Blockstream: Official website: https://blockstream.com/ (opens in a new window).⁠[27]

X: Public account: https://x.com/adam3us (opens in a new window).⁠[28]