Wei Dai

Wei Dai
EducationUniversity of Washington
OccupationComputer engineer
Known forb-money, Crypto++, VMAC
Websitewww.weidai.com

Wei Dai (Chinese: 戴维) is a computer engineer known for contributions to cryptography and cryptocurrencies. He developed the Crypto++ cryptographic library, proposed the b-money cryptocurrency system, and co-proposed the VMAC message authentication algorithm.

Education and career

Dai graduated from the University of Washington with a degree in computer science, just before proposing b-money in 1998.

In 2015, The New York Times described Dai as an "intensely private computer engineer". Wei Dai was a member of the Cypherpunks and Extropians mailing lists in the 1990s, and later SL4. On SL4 he exchanged with people such as Eliezer Yudkowsky, Robin Hanson, Nick Bostrom, Aubrey de Grey, Anders Sandberg, and others in a nascent rationalist community.

Dai has contributed to the field of cryptography and identified a cipher block chaining (CBC) vulnerability in SSH2; his work also informed the browser exploit against SSL/TLS known as BEAST (Browser Exploit Against SSL/TLS), developed by Juliano Rizzo and Thai Duong in 2011.

Dai said that he had declined an invitation to invest in Anthropic's initial funding round because he did not want to contribute to existential risk from artificial intelligence or signal approval of Anthropic's approach to AI safety.

Crypto++

Crypto++ is an open-source C++ library that provides implementations of cryptographic algorithms. It was originally written by Dai and first released in 1995. In June 2015 Dai stepped away from the Crypto++ project to work on other projects, with the Crypto++ community continuing to maintain the project.

b-money

In 1998, Dai helped to spark interest in cryptocurrencies with the publication of "b-money, an anonymous, distributed electronic cash system". In the paper, Dai outlines the basic properties of his proposed system: "...a scheme for a group of untraceable digital pseudonyms to pay each other with money and to enforce contracts amongst themselves without outside help".

The paper describes two protocols: one in which all participants maintain account balances, and another in which a subset of servers maintains them.

VMAC

VMAC is a block cipher-based message authentication code (MAC) algorithm using a universal hash proposed by Ted Krovetz and Wei Dai in April 2007. The algorithm was designed for high performance backed by a formal analysis.

Influence on the development of Bitcoin

Described as "money which is impossible to regulate", Dai's b-money described some concepts later implemented in Bitcoin and other cryptocurrencies. The proposal included:

Relationship with Satoshi Nakamoto

Wei Dai and Adam Back were the first two people contacted by Satoshi Nakamoto as he was developing Bitcoin in 2008 and the b-money paper was referenced in the subsequent Bitcoin whitepaper.

In a May 2011 article, cryptographer Nick Szabo stated:

Myself, Wei Dai, and Hal Finney were the only people I know of who liked the idea (or in Dai's case his related idea) enough to pursue it to any significant extent until Nakamoto (assuming Nakamoto is not really Finney or Dai).

However, Dai questions b-money's influence on Bitcoin:

...my understanding is that the creator of Bitcoin, who goes by the name Satoshi Nakamoto, didn't even read my article before reinventing the idea himself. He learned about it afterward and credited me in his paper. So my connection with the project is quite limited.

There has been much speculation as to the identity of Satoshi Nakamoto, with candidates including Wei Dai himself, Nick Szabo, and Hal Finney, all of whom have denied the putative identification.

References

  1. ↑ Wei Dai (2014-03-18). "Ask A LessWronger Anything".
  2. ↑ Morgen E. Peck (May 30, 2012). "Bitcoin: The Cryptoanarchists' Answer to Cash". IEEE Spectrum.
  3. 1 2 3 Popper, Nathaniel (May 15, 2015). "Decoding the Enigma of Satoshi Nakamoto and the Birth of Bitcoin". New York Times. Retrieved 31 August 2015.
  4. ↑ Chivers, Tom (2019). The AI Does Not Hate You: Superintelligence, Rationality and the Race to Save the World. United Kingdom: Weidenfeld & Nicolson. ISBN 978-1-4746-0877-0.
  5. ↑ ZiJie, Xu. "Some Fixes To SSH" (PDF). International Association for Cryptologic Research. Retrieved 16 September 2015.
  6. ↑ Goodin, Dan (Sep 21, 2011). "Google preps Chrome fix to slay SSL-attacking BEAST". The Register. Retrieved 16 September 2015.
  7. ↑ Bard, Gregory V. (2006). "A Challenging but Feasible Blockwise-Adaptive Chosen-Plaintext Attack on SSL" (PDF). pp. 7–10. Retrieved 11 August 2026.
  8. ↑ Dai, Wei (28 August 2025). "Comment on "Open Global Investment as a Governance Model for AGI"". LessWrong. Retrieved 12 September 2026.
  9. ↑ "weidai11 / cryptopp". GitHub.
  10. ↑ "Crypto++ Library | All Downloads". cryptopp.com. Retrieved 2024-07-14.
  11. ↑ "Crypto++ 5.6.3 Release Notes". November 20, 2015. Retrieved June 1, 2021.
  12. 1 2 Peterson, Andrea (January 3, 2014). "Hal Finney received the first Bitcoin transaction. Here's how he describes it". The Washington Post. Retrieved 16 September 2015.
  13. 1 2 3 Dai, Wei. "B-Money". Archived from the original on March 28, 2018.
  14. ↑ Dai, Wei. "b-money, monetary exchange and contract enforcement for digital pseudonyms". Archived from the original on February 19, 1999.
  15. ↑ Wei Dai (1998). "B-Money".
  16. ↑ Wei Dai (1998). "b-money, monetary exchange and contract enforcement for digital pseudonyms".
  17. ↑ Dai, Wei; Krovetz, Ted (2007-04-23). VMAC: Message Authentication Code using Universal Hashing (Report). Internet Engineering Task Force.
  18. ↑ Dai, Wei; Krovetz, Ted (2007-08-29). "VHASH Security". International Association for Cryptologic Research. Archived from the original on 2016-08-17.
  19. ↑ Daniel Cooper (May 8, 2013). "The rise (and rise?) of Bitcoin". Engadget.
  20. ↑ DuPont, Quinn (2014). "The politics of cryptography: Bitcoin and the ordering machines". Journal of Peer Production. 1 (4).
  21. ↑ Satoshi Nakamoto. "Bitcoin: A Peer-to-Peer Electronic Cash System" (PDF).
  22. ↑ Nick Szabo (2011-05-28). "Bitcoin, what took ye so long?". Unenumerated. Retrieved 2014-03-12.
  23. ↑ "Making money with Bitcoin?". LessWrong. February 2011.
  24. ↑ Smith, Andrew (2 March 2014). "Desperately seeking Satoshi". The Sunday Times. p. 16.
  25. ↑ Wile, Rob (16 April 2014). "The Hunt For The Creator Of Bitcoin Keeps Coming Back To One Guy — And He May Be Hiding In Plain Sight". Business Insider.
  26. ↑ Weisenthal, Joe (19 May 2013). "Here's The Problem With The New Theory That A Japanese Math Professor Is The Inventor Of Bitcoin". Business Insider. Archived from the original on 2013-11-03. Retrieved 19 May 2013.
  27. ↑ Vigna, Paul (Apr 16, 2014). "Bitcoin Creator 'Satoshi Nakamoto' Unmasked–Again?". Wall Street Journal. Retrieved 16 September 2015.