Josef Pieprzyk

Josef Pieprzyk, born in 1949 in Poland, is a cryptographer and a professor at Queensland University of Technology in Brisbane, Australia. His name is attached to several well known designs and attacks in cryptography. He collaborated in the invention of the LOKI and LOKI97 block ciphers: the LOKI97 article credits Lawrie Brown as designer, assisted by Jennifer Seberry and Pieprzyk, and records that the cipher was a candidate in the Advanced Encryption Standard competition and was rejected when candidates were shortlisted. HAVAL, a cryptographic hash function that can produce hashes of several lengths, was invented by Yuliang Zheng, Pieprzyk and Seberry in 1992 and was broken in 2004. In 2002 he and Nicolas Courtois published the XSL attack, an algebraic method of cryptanalysis for block ciphers that was claimed to have the potential to break the Advanced Encryption Standard faster than an exhaustive search, and which caused controversy even though its high work factor means it does not affect the real world security of block ciphers in the near future.