Creator of b-money and Crypto++, cited in the Bitcoin white paper
Identity hypothesis →Wei Dai is a computer scientist and cryptographer known for two major contributions to the field: the b-money proposal for digital currency and the Crypto++ cryptographic library. He studied computer science at the University of Washington and worked at Microsoft. The b-money citation as reference [1] in the Bitcoin whitepaper, the Crypto++ codebase dependency in Bitcoin v0.1, and Wei Dai’s status as the second person Satoshi contacted before launch have made him a recurring Satoshi-identity candidate — documented in the Wei Dai = Satoshi hypothesis entry, with the January 2014 AALWA retrospective as the principal self-denial.
In November 1998, Dai published “b-money”, a proposal for an anonymous, distributed electronic cash system, on the cypherpunks mailing list. The b-money proposal described a system where participants could create money by broadcasting the solution to a computational puzzle — a concept conceptually similar to Bitcoin’s proof-of-work mining. The paper outlined two protocols: one requiring a synchronous broadcast channel, and another using a set of servers to keep track of balances. B-money was never implemented, but it became one of the key intellectual precursors to Bitcoin.
Dai created and maintained Crypto++, a free, open-source C++ library providing a comprehensive collection of cryptographic algorithms and schemes. The library is widely used in academic and commercial projects and remains one of the most respected cryptographic libraries available. Bitcoin used Crypto++ for its SHA-256 implementation from the earliest archived release: Bitcoin v0.1.3 ALPHA (early 2009) carries src/sha.cpp and src/sha.h with a header note stating that the routines were “extracted as a standalone file from Crypto++ Version 5.5.2 (9/24/2007)” — the latest Crypto++ release available at the time Bitcoin was being designed (mid-2007 onward).
The Crypto++ 5.6.0 SSE2-assembly-optimized SHA-256 was integrated into Bitcoin in version 0.3.6 (July 29, 2010 release). Primary-source timeline:
Dai’s code contributions to Bitcoin are twofold: b-money as an intellectual precursor, and Crypto++ as a direct codebase dependency from the earliest released version.
On August 22, 2008, Satoshi Nakamoto emailed Dai directly, writing that he was preparing to publish a paper expanding on Dai’s b-money ideas. Satoshi asked Dai for the year of b-money’s publication to properly cite it. This email, along with a similar one sent to Adam Back two days earlier, represents the earliest known evidence of Satoshi reaching out to existing cryptographers before publishing the Bitcoin white paper. The white paper, published on October 31, 2008, cites b-money as its first reference.
In January 2009, following Bitcoin’s launch, Dai and Satoshi exchanged further emails. Satoshi wrote to Dai about the upcoming release, and Dai responded with thoughts on Bitcoin’s design, noting both its similarities to and differences from b-money. Dai also made philosophical observations about the nature of money and cryptocurrency that demonstrated a deep understanding of the challenges involved.
Dai’s b-money proposal is one of the most direct intellectual predecessors to Bitcoin. Satoshi’s decision to contact Dai before publication, and the prominent citation of b-money in the white paper, underscores the degree to which Bitcoin built upon Dai’s earlier work. Dai’s later 2014 retrospective on Satoshi — that he was “not anyone who was previously active in the academic cryptography or cypherpunks communities” — together with Satoshi’s own admission of not knowing b-money during 18 months of development, anchors an analysis of Satoshi’s relationship to the cypherpunk movement and the alignment of his practice with its philosophical core. The unit “wei” in the Ethereum cryptocurrency was named in honor of Wei Dai.
19 entries
Wei Dai announces Disperse/Collect 1.0 on the Cypherpunks list, built from his own Crypto++ library. Confirms he was an active coder, relevant to why he later chose not to implement b-money.
Wei Dai announces b-money on the Cypherpunks list as a secondary item alongside PipeNet 1.1, his primary focus. The proposal later cited in Bitcoin appears in a single sentence at the end of the post.
Adam Back replies to Wei Dai on Cypherpunks, identifying seven monetary-design issues in b-money and proposing Hashcash as the minting mechanism — a substantive analysis ten years before Bitcoin.
Wei Dai replies to Adam Back on Cypherpunks, conceding b-money would be at most a niche mechanism and revealing his shift toward viewing the government monopoly of force as a net benefit.
The hypothesis that Wei Dai — b-money author (whitepaper ref [1]) and Crypto++ creator — was Satoshi. Counter: Aug 22, 2008 email reads as third-party reception; 2014 AALWA self-distinction.
Satoshi emails Wei Dai asking for the correct b-money citation, revealing he learned of it via Adam Back. The email linked the pre-release draft 'Electronic Cash Without a Trusted Third Party'.
Bitcoin v0.1 reuses one cypherpunk primitive (PoW from Hashcash), borrows general CS components (Merkle trees, linked timestamping), and synthesizes the rest (UTXO, mining, 21M cap, P2P, ECDSA).
Editorial reading of Satoshi's relationship to cypherpunk, from three primary observations: he didn't know b-money, Wei Dai testified Satoshi was "not previously active," alignment with Hughes 1993.
Comparison of recurring Satoshi candidates aligned in a seven-dimension profile table. The Individual column links each candidate's hypothesis page; this entry names no leading candidate.
On LessWrong, Wei Dai clarifies he did not create Bitcoin — "only described a similar idea more than a decade ago" — buys a Radeon 5870 to mine, and warns Bitcoin lacks cryptographer security review.
Nick Szabo discusses why Bitcoin took so long, the similarities and differences between bit gold and Bitcoin, and why "nearly everybody who heard the general idea thought it was a very bad idea."
On November 20, 2011, Bitcoin v0.5 shipped with the Crypto++ SHA-256 subset removed and replaced by OpenSSL. Wei Dai's library, a direct codebase dependency since v0.1, was gone.
Benjamin Wallace's Wired feature — an early major mainstream article on Bitcoin. Traces the whitepaper, mining boom, Mt. Gox hack, and growing pains, ending with Garzik's "We really don't care."
Wei Dai LessWrong comments: Bitcoin's monetary policy has failed due to volatility, and he never replied to Satoshi's 2008 review email — regretting he could have dissuaded the fixed-supply choice.
Wei Dai's LessWrong Q&A reflections: Satoshi did not read the b-money paper before reinventing the idea, and Dai had grown disillusioned with cryptoanarchy by the time he wrote it up.
Wei Dai LessWrong post revealing Satoshi emailed him about Bitcoin v0.1 in early 2009, but Dai ignored it because he was more interested in Less Wrong than Cypherpunks at the time.
On May 15, 2015, the New York Times published Nathaniel Popper's Decoding the Enigma of Satoshi Nakamoto — a Digital Gold excerpt naming Bit Gold designer Nick Szabo as Satoshi. Szabo denied it.
Adam Back reflects on his August 2008 email exchange with Satoshi, his regret at not reading the whitepaper carefully, and his COPA v Wright testimony where the complete chain became public.
Bitcoin Institute reanalysis of van Dorst's stylometric corpus for the five most-cited candidates. Finding: Szabo top at 4.67th percentile of 12,739 authors; 594 unnamed rank closer; corpus is noisy.