Ray Dillinger

Computer scientist who, along with Hal Finney, reviewed Satoshi Nakamoto's Bitcoin source code before its public release. He focused on security auditing and is credited with contributing to the origin of the 1 MB block size limit.

Ray Dillinger is a computer scientist known by his online handles “bear” and “cryddit.” He studied computer science at the University of Kansas and has been active in the cryptography and cypherpunk communities for decades. He is one of two people — along with Hal Finney — known to have reviewed Satoshi Nakamoto’s Bitcoin source code before its public release.

Pre-Release Code Review: In late 2008, Satoshi Nakamoto shared Bitcoin’s source code privately with a small number of people before the public release in January 2009. Dillinger conducted a security audit of the code, examining it for potential vulnerabilities and attack vectors. Hal Finney simultaneously reviewed the code from a different perspective. In a later BitcoinTalk post, Dillinger recalled spending approximately two weeks reviewing the code, focusing on ways the system might be exploited.

Block Size Limit: Dillinger has been connected to the origin of Bitcoin’s 1 MB block size limit, one of the most debated parameters in Bitcoin’s history. In later public statements, he described how early discussions about potential denial-of-service attacks led to consideration of limiting block size to prevent spam transactions from overwhelming the network.

Mailing List Participation: Dillinger participated in the cryptography mailing list discussion about Bitcoin in November 2008, posting under the name “Ray Dillinger.” His posts engaged with the technical details of Bitcoin’s design, including questions about the incentive structure and security model.

Later Reflections: In September 2017, Dillinger published a reflective post on BitcoinTalk titled “If I’d known then what I know now,” in which he discussed what he might have done differently had he understood Bitcoin’s future significance. He reflected on the early code review process and the design decisions that shaped Bitcoin’s development. In an October 2022 interview with security researcher SerHack, Dillinger provided additional details about the pre-release review process and his early interactions with Satoshi.

Related Entries

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Aftermath

The alternative genesis block — Satoshi's pre-release test block from September 2008

SerHack Satoshi Nakamoto, Ray Dillinger, Hal Finney

SerHack published an analysis of a pre-release Bitcoin genesis block dated September 10, 2008 — discovered in source code Satoshi shared privately in November 2008. The test block had a completely different hash, trivially easy difficulty, and an initial block reward of 10,000 units. The September 10 date coincides with Lehman Brothers announcing $3.9 billion in losses.