He was an assistant professor in the Mathematics Department of the University of Massachusetts Boston from 1973 to 1978.
In 2022 he was a Research Scientist in the Statistics and Privacy Group of Meta Platforms.
[1] His main areas of interest are in computational number theory, combinatorics, data compression and cryptography.
[2] He is also one of the co-inventors, with Mark Wegman, of the LZW data compression algorithm, and various extensions,[3] one of which is used in the V.42bis international modem standard.
[13] He is also a member of Information Systems Security Association Hall of Fame [14]