Golden Recursion Inc. logoGolden Recursion Inc. logo
Advanced Search
Adam Back

Adam Back

Adam Back is a British cryptographer and cypherpunk

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.


Back was born in London, England, in July 1970. 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.

He has a computer science PhD in distributed systems from the University of Exeter. 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, Adam 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.

Work experience



Jan 2014 – present time

Applied Cryptographer

Bitcoin Consultant

Apr 2013 – present time

Owner and Consultant

Cypherspace Internet Security

Dec 1997 – present time

Chief Info Sec Officer

EMC (Decho Corporation)

June 2008 - July 2010

Security Architect & Co-Founder

PI Corporation

Dec 2003 - July 2010

Cryptographic Consultant

GuardianEdge Technologies

1992 - 2008

Security Architect


Dec 2002 - Nov 2003

Security Architect

Zero Knowledge Systems

Dec 1999 - Nov 2002

Research Assistant

Haldon House Research

1998 - 1999

Cryptography software

Back is a pioneer of early digital asset research similarly as Wei Dai, David Chaum, and Hal Finney. In 1997, Back invented Hashcash. A similar system is used in bitcoin.

He also implemented credlib, a library that implements the credential systems of Stefan Brands and David Chaum.

He was the first to describe the "non-interactive forward secrecy" 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 and 3-line RSA in Perl signature file and non-exportable T-shirts to protest cryptography export regulations.

Back was one of the first two people to receive an email from Satoshi Nakamoto. In 2016, the Financial Times cited Back as a potential Nakamoto candidate, along with Nick Szabo and Hal Finney. Craig Wright had sued Back for stating that Wright was not Nakamoto, with Wright subsequently dropping the suit.

Back has promoted the use of satellites and mesh networks to broadcast and receive bitcoin transactions, as a backup for the traditional internet.

Personal Investments

Adam Back made 3 investments.

Sep 21, 2021 Portal — Venture Round - $8.5M

Aug 6, 2020 Infinite Fleet — Initial Coin Offering - $3.1M

Aug 3, 2020 Pixelmatic — Private Equity Round - $3.1M


October 24, 2021
Blockstream CEO Adam Back Goes Against Meme Coins: A Low Res Gif of a Rock Has No Merit
August 24, 2021
Blockstream Raises $210M, Acquires Mining Chip Manufacturer Spondoolies
July 1, 1970
Adam Back was born in London.

Invested in


Further Resources


A Conversation with Adam Back, CEO of Blockstream


September 19, 2021

Barely Sociable Analyst Believes Blockstream CEO Adam Back Is Satoshi Nakamoto

Daria Rud


December 29, 2021

Crypto Crime Cartel: Behind Adam Back and Blockstream's attempts to constrain Bitcoin

Steven Stradbrooke


May 18, 2021

DECENTRALIZED 2019 | Interview Video - Dr. Adam Back


November 1, 2019

Reflections on Satoshi with Adam Back and Pete Rizzo - Bitcoin Magazine Podcast


May 4, 2021


Golden logo
By using this site, you agree to our Terms & Conditions.