b-money

b-money was announced on the Cypherpunks mailing list in 1998; SNI dates its text to November. Dai later confirmed the year to Satoshi and supplied the announcement link. It is presented here as a proposal, with its publication date kept separate from the later disclosure of their correspondence.

Public keys identify participants, who sign and broadcast payments. Everyone keeps balances in the first protocol; selected servers do so in the second. Verifiable computation creates money, while contracts reserve funds for compensation.

The first protocol assumes idealized anonymous broadcasting; the second still requires some trust in servers. Computation is difficult to price consistently, prompting an auction alternative in the appendix. These are constraints acknowledged in the proposal itself.

The Bitcoin whitepaper formally cites b-money. On 22 August 2008, Satoshi told Dai that Adam Back had directed him to the proposal and asked for its publication year. This establishes awareness and citation, but does not prove that Bitcoin's initial design came entirely from b-money.

In January 2009, Satoshi said Bitcoin met nearly all of b-money's goals. He quoted Hal Finney's distinction: Bitcoin works with transactions and coins rather than accounts, and uses proof-of-work to help maintain globally consistent records. Shared goals therefore coexist with substantial changes in mechanism.

Wei Dai works on cryptography and anonymous communication and originally wrote the Crypto++ library. He participated in the Cypherpunks mailing list and proposed b-money and the PipeNet anonymity protocol.