CryptoDB
Constructing Variable-Length PRPs and SPRPs from Fixed-Length PRPs
Authors: | |
---|---|
Download: | |
Abstract: | We create variable-length pseudorandom permutations (PRPs) and strong PRPs (SPRPs) accepting any input length chosen from the range of b to 2b bits from fixed-length, b-bit PRPs. We utilize the elastic network that underlies the recently introduced concrete design of elastic block ciphers, exploiting it as a network of PRPs. We prove that three and four-round elastic networks are variable-length PRPs and five-round elastic networks are variable-length SPRPs, accepting any input length that is fixed in the range of b to 2b bits, when the round functions are independently chosen fixed-length PRPs on b bits. We also prove that these are the minimum number of rounds required. |
BibTeX
@misc{eprint-2008-18055, title={Constructing Variable-Length PRPs and SPRPs from Fixed-Length PRPs}, booktitle={IACR Eprint archive}, keywords={secret-key cryptography / (strong) PRPs, block ciphers, variable-length PRPs}, url={http://eprint.iacr.org/2008/496}, note={shorter version will appear in Inscrypt 2008 dcook@cs.columbia.edu 14209 received 25 Nov 2008}, author={Debra L. Cook and Moti Yung and Angelos Keromytis}, year=2008 }