Path: illuminati.io.com!nobody From: ritter@indial1.io.com (Terry Frank Ritter) Newsgroups: sci.crypt Subject: DESX Date: 6 Mar 1994 02:58:52 -0600 Organization: Illuminati Online Lines: 42 Message-ID: <2lc60c$1u6@indial1.io.com> NNTP-Posting-Host: indial1.io.com In <2ku9uc$sr8@msuinfo.cl.msu.edu> mrr@scss3.cl.msu.edu (Mark Riordan) writes: >DESX is an encryption algorithm that extends the famous DES >(Data Encryption Standard) algorithm to a keysize of 120 bits. >It does this by simply XORing the input block with a bit pattern >(pre-Whitening), encrypting with standard DES, and then XORing >the result with another bit pattern (post-Whitening). A | v ka -> XOR | v B | v k1 -> DES | v C | v kb -> XOR | v D Single capital letters represent 64-bit blocks. k1 is a 56-bit DES key. ka and kb are 64-bit keys developed by hashing k1 and k2, a 64-bit key. k1 and k2 total 120 bits. Presumably the salient issue is that the outside XOR's are intended to protect the internal DES from exhaustive search. --- Terry Ritter ritter@io.com