Adam Back
British cryptographer and cypherpunk (born 1970)
From Wikipedia, the free encyclopedia
Adam Back (born July 1970) is a British cryptographer and cypherpunk. He is the CEO of Blockstream, which he co-founded in 2014. He invented Hashcash, which is used in the bitcoin mining process.
- Zero-Knowledge Systems
- Pi Corporation
- Blockstream
Adam Back | |
|---|---|
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| Born | July 1970 (age 55) London, England, UK |
| Education | University of Exeter |
| Scientific career | |
| Fields | |
| Institutions |
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| Thesis | Parallelization of general purpose programs using optimistic techniques from parallel discrete event simulation (1995) |
| Doctoral advisor | Stephen Turner |
| Website | cypherspace |
Life
Back was born in London, England, in July 1970.[1] His first computer was a Sinclair ZX81. He taught himself Basic, and spent his time reverse engineering video games, finding decryption keys in software packages. He completed his A levels in advanced mathematics, physics, and economics.[citation needed]
He has a computer science PhD in distributed systems from the University of Exeter.[2] During his PhD, Back worked with compilers to make use of parallel computers in a semi automated way. He became interested in PGP encryption, electronic cash and remailers. He spent two thirds of his time working with encryption. After graduation, Back spent his career as a consultant in start ups and larger companies in applied cryptography, writing cryptographic libraries, designing, reviewing and breaking other people's cryptographic protocols.[3]
Cryptography software
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Back is a pioneer of early digital asset research similar to Wei Dai, David Chaum, and Hal Finney.[4][5] In 1997, Back invented Hashcash.[6] A similar system is used in Bitcoin.[7][8][9]
He also implemented credlib,[10][better source needed][11][better source needed] a library that implements the credential systems of Stefan Brands and David Chaum.
He was the first to describe the "non-interactive forward secrecy"[12][13][14] security property for email and to observe that any identity-based encryption scheme can be used to provide non-interactive forward secrecy.
He is also known for promoting the use of ultra-compact code with his 2-line[15] and 3-line RSA in Perl[16][17][18] signature file[disambiguation needed] and non-exportable T-shirts[19][20] to protest cryptography export regulations.[21]
Back was one of the first two people to receive an email from Satoshi Nakamoto.[22][2] In 2016, the Financial Times cited Back as a potential Nakamoto candidate, along with Nick Szabo and Hal Finney.[23] Craig Wright had sued Back for stating that Wright was not Nakamoto, with Wright subsequently dropping the suit.[2] In 2020, the YouTube channel Barely Sociable claimed that Back is Nakamoto. Back subsequently denied this.[24]
Back has promoted the use of satellites and mesh networks to broadcast and receive bitcoin transactions, as a backup for the traditional internet.[25]
Business career
On 3 October 2016, Back was appointed as CEO of Blockstream.[26]
Jeffrey Epstein-related investment and correspondence
In February 2026, The Guardian and Decrypt reported that documents released by the U.S. Department of Justice in connection with the "Epstein files" included email communications indicating that Jeffrey Epstein had invested indirectly in Blockstream during its 2014 seed round via a fund associated with Joi Ito, and that Back and Blockstream co-founder Austin Hill were invited to meet Epstein in the U.S. Virgin Islands. Back stated publicly that Epstein was described at the time as a limited partner in Ito’s fund, and that the fund later divested its Blockstream shares within months due to conflict-of-interest concerns, adding that Blockstream had no direct or indirect financial connection to Epstein or his estate. The same reporting noted that the appearance of names in released documents does not, by itself, indicate wrongdoing. [27] [28]