Date: Mon, 7 Apr 2003 16:32:09 -0400 Reply-To: Joshua R Holden Sender: Number Theory List From: Joshua R Holden Subject: Re: Cryptgraphy: simplified AES Thanks very much to everyone who wrote with help on my simplified AES question! My apologies for not writing to everyone individually, but I will try to answer some general questions that people asked and summarize some of the information I received. The original verion of AES is indeed easy to explain, even without simplification and even to undergraduates. However, I wanted a version for which students could get most of the way through the encryption process in a single class meeting. This is not feasible for the original AES simply because of size. (At least, it was not for my students.) The original article on Simplified DES was "A Simplified Data Encryption Algorithm", by Edward Schaefer, Cryptologia, Volume XX Number 1 (January 1996). The two different versions of simplified AES may be found in "Mini Advanced Encryption Standard (Mini-AES): A Testbed for Cryptanalysis Students", by Raphael Chung-Wei Phan, Cryptologia, Volume XXVI Number 4 (October 2002) and in ``A simplified AES algorithm and its linear and differential cryptanalyses'', by Mohammad Musa, Edward Schaefer, and Stephen Wedig, Cryptologia, to appear. Both versions use 16 bit key and block sizes and two rounds with essentially the same structure as AES. There are differences in the S-boxes used, in the matrix used in the MixColumn operation, and in the key scheduling. (Possibly there are others but I did not notice any.) Thanks very much also to everyone who offered other advice, or offered to write a custom S-AES for me! I appreciate everyone's help. ---Josh -- Joshua Brandon Holden RHIT Math Department Faculty holden@rose-hulman.edu Donate food for free! Go to . JBH/hypatia