Adam Back

Adam Back is a cryptographer best known for Hashcash, the proof-of-work scheme Satoshi cited in the Bitcoin whitepaper. On 20 August 2008 Satoshi sent him the first known Satoshi email collected in this archive, asking whether a Hashcash citation was correct and sharing a draft paper then titled Electronic Cash Without a Trusted Third Party. Back pointed Satoshi toward Wei Dai's b-money, which helped complete the whitepaper's citation trail.

In the years after Satoshi left, Back co-founded Blockstream in 2014 with a team that included other long-time Bitcoin engineers. As Blockstream's CEO he has pushed sidechains, Liquid, mining products and open-source protocol work, and he remains one of the most visible public advocates of proof of work and Bitcoin as digital commodity money. He speaks often about why energy expenditure is a feature of Bitcoin's security model, not an accident.

He was Satoshi's first documented contact, which is why this archive opens with that Hashcash email rather than with the October whitepaper alone. He has not been a guest on Bitcoin Takeover. This site does not treat him as a Satoshi suspect. The Hashcash paper remains required reading if you want to understand why Bitcoin burns energy on purpose, and why Satoshi reached for that particular prior art before announcing the network.