Len Sassaman

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Len Sassaman
Len Sassaman 27C3.jpg
Sassaman at the 27th Chaos Communication Congress
BornApril 9, 1980 (1980-04-09)
DiedJuly 3, 2011 (2011-07-04) (aged 31)
Leuven, Flemish Brabant, Belgium
Occupation(s)Researcher, COSIC
Known forMixmaster, X.509 attacks
SpouseMeredith L. Patterson (m. 2006)

Leonard Harris Sassaman (April 9, 1980 – July 3, 2011) was an American technologist, information privacy advocate, and the maintainer of the Mixmaster anonymous remailer code and operator of the randseed remailer. Much of his career gravitated towards cryptography and protocol development.

Early life and education[edit]

Sassaman graduated from The Hill School in 1998. By 18, he was on the Internet Engineering Task Force responsible for the TCP/IP protocol underlying the internet and later the Bitcoin network. He was diagnosed with depression as a teenager.[1] In 1999, Len moved to the Bay Area, quickly became a regular in the cypherpunk community and moved in with Bram Cohen.


Sassaman was employed as the security architect and senior systems engineer for Anonymizer. He was a PhD candidate at the Katholieke Universiteit Leuven in Belgium, as a researcher with the Computer Security and Industrial Cryptography (COSIC) research group, led by Bart Preneel. David Chaum and Bart Preneel were his advisors.

Sassaman was a well-known cypherpunk, cryptographer and privacy advocate. He worked for Network Associates on the PGP encryption software, was a member of the Shmoo Group, a contributor to the OpenPGP IETF working group, the GNU Privacy Guard project, and frequently appeared at technology conferences like DEF CON. Sassaman was the co-founder of CodeCon along with Bram Cohen, co-founder of the HotPETS workshop (with Roger Dingledine of Tor and Thomas Heydt-Benjamin), co-author of the Zimmermann–Sassaman key-signing protocol, and at the age of 21, was an organizer of the protests following the arrest of Russian programmer Dmitry Sklyarov.[2]

Len slips a blue cable-tie ring on Meredith's finger

On February 11, 2006, at the fifth CodeCon, Sassaman proposed to returning speaker and noted computer scientist Meredith L. Patterson during the Q&A after her presentation, and they were married.[3] The couple worked together on several research collaborations, including a critique of privacy flaws in the OLPC Bitfrost security platform,[4] and a proposal of formal methods of analysis of computer insecurity in February 2011.[5]

Meredith Patterson's current startup, Osogato, aims to commercialize Patterson's Support Vector Machine-based "query by example" research. Sassaman and Patterson announced Osogato's first product, a downloadable music recommendation tool, at SuperHappyDevHouse 21 in San Francisco.

In 2009, Dan Kaminsky presented joint work with Sassaman and Patterson at Black Hat in Las Vegas, showing multiple methods for attacking the X.509 certificate authority infrastructure. Using these techniques, the team demonstrated how an attacker could obtain a certificate that clients would treat as valid for domains the attacker did not control.[6][7]

CNBC India suggested Sassaman as a potential candidate to be Satoshi Nakamoto.[8]


Len memorial on the Bitcoin blockchain

Sassaman is reported to have died on July 3, 2011.[9][10] Patterson reported that her husband's death was a suicide.[11][12]

A presentation given by Kaminsky at the 2011 Black Hat Briefings revealed that a testimonial in honor of Sassaman had been permanently embedded into Bitcoin's blockchain.[13]

See also[edit]


  1. ^ leung (2021-03-04). "Len Sassaman and Satoshi". Medium. Retrieved 2021-03-04.
  2. ^ McCullagh, Declan; Benner, Jeffrey (24 July 2001). "Sklyarov Release in Feds' Hands". Wired.
  3. ^ Archived at Ghostarchive and the Wayback Machine: Slutsky, Irina (11 December 2008). "Len Sassaman & Meredith Patterson are CodeCon Valentines". GeekEntertainment.TV – via YouTube.
  4. ^ Barras, Colin (5 June 2008). "Laptops could Betray Users in the Developing World". New Scientist (2659).(registration required)
  5. ^ Sassaman, Len; Patterson, Meredith L. (February 17, 2011). "Towards a formal theory of computer insecurity: a language-theoretic approach" (Flash video). Institute for Security, Technology and Society, Dartmouth College.
  6. ^ Goodin, Dan (30 July 2009). "Wildcard certificate spoofs web authentication - SSL felled by null string". The Register.
  7. ^ Rodney. "Dan Kaminsky Feels a disturbance in The Internet". Semiaccurate.com.
  8. ^ "Is crypto expert Len Sassaman the creator of Bitcoin, Satoshi Nakamoto?". CNBCTV18.
  9. ^ l33tdawg (3 July 2011). "RIP: Len Sassaman, crypto expert and privacy advocate". Hack In The Box SecNews.
  10. ^ Orlowski, Andrew (July 6, 2011). "Cryptographer Len Sassaman, RIP". The Register. Retrieved 2013-10-27.
  11. ^ maradydd (Meredith Patterson) (3 July 2011). "Len Sassaman has passed away". Hacker News, YCombinator.com.
  12. ^ Patterson, Meredith L (3 July 2011). "@wimremes unfortunately, it is. I got the call from the Leuven police about three hours ago. (I'm in TX visiting family at the moment.)". Twitter.com.
  13. ^ Kaminsky, Dan (August 4, 2011). "Black Ops of TCP/IP 2011". pp. 12–16.

External links[edit]