Professor at the Department of Mathematics at the Technical University of Denmark. His specialty is cryptology, specifically the design and analysis of block ciphers, hash functions, and message authentication codes. He has helped develop many well-known algorithms, such as Square (which was the ancestor of Rijndael) and the AES candidate Serpent, and has developed and refined many cryptanalytic methods. His home page is at http://www.ii.uib.no/~larsr/.