Cottrell ships Mixmaster and turns Chaum's 1981 theory into software anyone can run

MAY 03 1995 · 12:05

Video: How to explain the 👪 Friends and Family Round 🤷 Date: 1995-05-03 · Type: primitive · Tags: mixmaster, lance-cottrell, anonymous-remailer, type-II, traffic-analysis, cypherpunks, 1995, tor-predecessor If the manifestos were the prose, Mixmaster was the verb. Lance Cottrell, then a UC San Diego physics graduate student, wrote Mixmaster as a Type II anonymous remailer — a software implementation of Chaum's 1981 mix-network paper, with fixed-size packets, message reordering, and dummy-traffic padding designed to defeat traffic analysis by an adversary who could observe the entire network. The first experimental release came in late 1994; Mixmaster 2.0 was formally released on 3 May 1995 and became the cypherpunk infrastructure of choice for serious anonymity needs for nearly a decade. The Type I 'Cypherpunk remailer' that Eric Hughes had built in 1992 was already operational, but it was vulnerable to traffic-correlation attacks: an observer who could watch packets enter and exit a relay could, over time, reconstruct the correspondence. Mixmaster addressed this by batching, padding, and reordering at fixed packet sizes, so that any given relay's output revealed nothing about the timing or content of its inputs. It was, in implementation, the direct descendant of Chaum's theoretical construction — a translation of academic cryptography into software that human rights workers and journalists could deploy in coercive environments. The commercial trajectory was ironic in the mode of the era. Cottrell founded Anonymizer, Inc. in San Diego in 1995 to commercialize the work, and Anonymizer was eventually acquired by Abraxas Corporation, a government contractor, and then by Cubic Corporation, a defense and transportation conglomerate. The cypherpunk infrastructure became, in one lineage, a government product. In another lineage, Mixmaster's architecture fed directly into the academic onion-routing work at the Naval Research Laboratory that became Tor. Both outcomes were latent in the original design. Facts • First experimental release: late 1994; Mixmaster 2.0: 3 May 1995 • Author: Lance Cottrell (UC San Diego); successor versions co-authored with Ulf Möller and others • Type II remailer: fixed-size packets, batching, latency, replay protection — direct implementation of Chaumian mixing • Ran in parallel with Type I 'Cypherpunk' remailer (Eric Hughes, 1992) • Commercial spinoff: Anonymizer, Inc. (San Diego, 1995); later acquired by Abraxas/Cubic defense contractors Primary Documents • Mixmaster anonymous remailer — Wikipedia — https://en.wikipedia.org/wiki/Mixmaster_anonymous_remailer