Documentary claims Hal Finney, Len Sassaman co-created Bitcoin

Finding Satoshi is a documentary that presents an investigation concluding Hal Finney and Len Sassaman collaborated on creating Bitcoin. The film follows a four-year inquiry led by journalist William D. Cohan and investigators from Quest Research and Investigations. It evaluates technical records, online activity, linguistic clues and eyewitness testimony to support its findings.

Investigators reviewed six early candidates tied to pre-Bitcoin work, including Adam Back, Nick Szabo, Paul Le Roux and Wei Dai, before focusing on Finney and Sassaman. The team used code analysis, activity timelines, stylometric review and interviews with people who worked with the candidates. The documentary describes the use of C++ in the original Bitcoin code and includes commentary from the creator of that language who assessed Satoshi as a competent C++ programmer for the period.

A data scientist consulted on the project identified roughly 64 major participants in Bitcoin’s first two years and mapped posting and mining activity. That analysis found Satoshi’s most active hours aligned with Pacific Time. Investigators compared those digital rhythms with known activity records for the candidates and report that Finney and Sassaman matched the profile more closely than other suspects.

The film also highlights technical links. Finney developed RPOW, a reusable Proof-of-Work mining system, and former colleagues noted structural similarities between RPOW and Bitcoin. Finney did not make public code commits at his employer in the two months between the whitepaper’s publication on Oct. 31, 2008, and Bitcoin’s genesis block in early January 2009; investigators note that gap while presenting the timeline.

The documentary presents material on Sassaman’s background in anonymity research and his academic writing style. Investigators say Sassaman often used British spellings while living in Europe and had documented techniques for anonymizing writing, which the film suggests could affect authorship attribution of the whitepaper. Meredith Patterson, Sassaman’s widow, appears in the film and discusses his work and connections in the cypherpunk community.

Former PGP colleagues contributed testimony. One co-founder described structural elements of Finney’s work and said Finney could switch programming languages as needed. Another recalled asking Finney late in life whether he was Satoshi; the film includes that exchange and the colleague’s later interpretation. The filmmakers state they found no evidence that family members have access to Satoshi’s private keys.

The investigation addresses conflicting timelines. Security researcher Jameson Lopp published an analysis arguing timestamped activity makes it unlikely that Finney and Satoshi were the same person. Investigators in the film discuss that a multi-person collaboration could explain some timing conflicts and present that scenario as part of their case.

Reactions quoted in the documentary include support from industry figures and cautious responses from others. The filmmakers note their case relies on circumstantial and stylistic evidence, expert testimony and coding timelines rather than cryptographic proof. Finding Satoshi was released globally on April 22 and presents the investigation’s evidence that Finney and Sassaman collaborated on Bitcoin while acknowledging it did not produce direct cryptographic verification.