Hans Dobbertin (17 April, 1952 – 2 February, 2006) was a German cryptographer who is best known for his work on cryptanalysis of the MD4, MD5, and original RIPEMD hash functions, and for his part in the design of the new version of the RIPEMD hash function.
He was a member of the German Federal Office for Information Security (Bundesamt für Sicherheit in der Informationstechnik, BSI) and professor at the Ruhr University in Bochum.
[1] Dobbertin studied mathematics and received his doctorate in 1983 with his thesis on refinement monoids, Vaught monoids and Boolean algebras at the mathematics department at the University of Hanover.
He completed his habilitation in Hanover in 1986 and moved to the Federal Office for Information Security (BSI), the German federal agency of IT security, as an associate professor.
In 2003, he opened the Horst Görtz Institute for IT Security (HGI) at the Ruhr University as founding director.