@misc{cryptoeprint:2008:496, author = {Debra L. Cook and Moti Yung and Angelos Keromytis}, title = {Constructing Variable-Length PRPs and SPRPs from Fixed-Length PRPs}, howpublished = {Cryptology ePrint Archive, Report 2008/496}, year = {2008}, url = {http://eprint.iacr.org/2008/496}, }