Adam Back

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.

Adam Back
Born	July 1970 (age 54) London, England, UK
Education	University of Exeter
Scientific career
Fields	Cryptographic protocols Electronic cash Privacy-enhancing technologies Distributed systems
Institutions	Zero-Knowledge Systems Pi Corporation Blockstream
Thesis	Parallelization of general purpose programs using optimistic techniques from parallel discrete event simulation (1995)
Doctoral advisor	Stephen Turner
Website	cypherspace.org/adam

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

Back's "Munitions" T-shirt featured computer code that was considered to be a weapon in the United States.

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 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]