Hugh C. Williams

Hugh Cowie Williams, born 23 July 1943, is a Canadian mathematician who works in number theory and cryptography. He studied mathematics at the University of Waterloo, taking a bachelor's degree in 1966 and a master's degree in 1967, and received his doctorate there in computer science in 1969. He taught at the University of Manitoba from 1970 and became a professor at the University of Calgary in 2001, where he has been professor emeritus since 2004 and held the iCore Chair in Algorithmic Number Theory and Cryptography. His work includes primality tests, for which the Williams primes are named, custom hardware for number theoretic calculations such as the MSSU of 1995, a public key cryptosystem based on real quadratic number fields developed in 1994 with Renate Scheidler and Johannes Buchmann, and algorithms for invariants of algebraic number fields such as class numbers and regulators. He also wrote on the history of primality testing.