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24 June 1998
To: cryptography@c2.net Subject: Matt Blaze: difference distribution table for Skipjack Date: Wed, 24 Jun 1998 20:18:17 -0400 From: "Perry E. Metzger" <perry@piermont.com> I thought this would be of interest to those examining the algorithm. To: coderpunks@toad.com Subject: difference distribution table for Skipjack Date: Wed, 24 Jun 1998 19:54:23 -0400 From: Matt Blaze <mab@research.att.com> I've generated the 256x256 difference distribution table for the Skipjack F function. This table gives the number of times each possible output XOR differential occurs for each possible input differential. It is in the format of Appendix B of Biham and Shamir's DES book, and is a simple ASCII table. The table is BIG (65536 entries - 200K bytes). You can ftp it from: <ftp://ftp.research.att.com/dist/mab/sj.dist> There are a few surprising spikes in the table, but they probably disappear after a few rounds. I haven't done anything beyond generating the table yet. (If you don't know what a difference distribution table is good for, you won't be able to make much use of this one until you understand differential cryptanalysis at the level of Biham and Shamir's book). -matt