The earliest documented email from Satoshi Nakamoto. Writing to Adam Back, Satoshi confirmed he was about to publish a paper that built on Hashcash and asked Back to verify the citation form he had drafted:
[A. Back, "Hashcash - a denial of service counter-measure,"
http://www.hashcash.org/papers/hashcash.pdf, 2002]The load-bearing line of the email reads:
Quote from: Satoshi Nakamoto on August 20, 2008, 5:30:39 PM UTCI’m getting ready to release a paper that references your Hashcash paper and I wanted to make sure I have the citation right.
Satoshi attached a link to a pre-release draft titled “Electronic Cash Without a Trusted Third Party” — the working title before the manuscript was renamed to “Bitcoin: A Peer-to-Peer Electronic Cash System” for the cryptography mailing-list draft where the abstract appears in its canonical form.
This is the earliest known direct contact between Satoshi and a central cypherpunk figure, and it is one of the primary-source observations underpinning the cypherpunk-independent-arrival analysis. Two days later Satoshi also wrote directly to Wei Dai (see the 2008-08-22 Satoshi → Wei Dai email).
This first-contact record is the upstream primary source for the Adam Back identity hypothesis, the 2026 NYT Carreyrou investigation, and Adam Back’s own 2024 retrospective testimony — each treats this email as the documented baseline of what Adam Back knew about Bitcoin’s design before its release. It is also referenced in the Adam Back biography, the Satoshi biography, the Satoshi self-statements analysis, and the bitcoin-design-lineage where the Hashcash citation Satoshi wrote becomes load-bearing evidence for the precursor-acknowledgement record.