Adam Back is a cryptographer and crypto-hacker.
He has a Ph.D. in Computer Science from University of Exeter.
Back invented Hashcash, a Proof of Work (PoW) and denial of service counter-measure system that inspired Bitcoin's creator, Satoshi Nakamoto, to come up with Bitcoin’s own Proof Of Work (PoW) functionality. Adam Back’s work was one of the eight references Nakamoto had on the original Bitcoin paper.
Back co-founded Blockstream, a blockchain technology company. Blockstream develops bitcoin applications, specifically sidechains such as Liquid sidechain, as well as other applications such as the Blockstream Satellite and funds many Bitcoin Core developers.
At the time of writing, Adam Back is the CEO of Blockstream.
Adam Back is a strong opponent of past and present projects to scale Bitcoin, such as Bitcoin Unlimited and Segwit2X.