A mimimal DES chip implementation can be found at: ripem.msu.edu:/pub/crypt/des/vhdl_des.tar.z -rw-r----- 1 mrr ftpsec 93630 Jan 12 02:01 vhdl_des.tar.z It was written to go with a paper on DES Hardware I'm putting the finishing touches on. Note that this site requires a password to belong to group ftpsec to download. It will encrypt in 47 clocks (8 IP, 29 Key Schedule, 8 FP) or decrypt in 46 clocks (28 Key Schedule), and will fit in some of the larger FPGAs. The paper, when finished, will describe various performance enhancements such as double buffered IP and FP (which is covered by an Ultron patent, although probably invalid), direct key schedule (16 clocks), or superscalar DES (approaching 1 clock per 64 bit block). For any hardware wonks, this is done in Synopsys VSS, although the README file contains enough information for other VHDL implmentations. There are also 4 or 5 'C' programs for generating VHDL files of the S Boxes in various configurations, and a sample 'C' DES program done in 1988 for the original UNIX libdes (source included). The 'C' program can be used to generate equivalent structures for debugging your own DES hardware variations. The test vectors are from NBS Special Pub 500-20 (circa 1978).