re freely distributable public key cryptography c code where victor iseli victori xetron com wrote numerical recipes in c fortran pascal has a nice section on encryption and decryption based on the des algorithm there is also source code provided i think some versions of this book are distributed with the source code on disk the source code can also be ordered from the publisher victor iseli victori xetron com yes i benchmarked the des implementation in the recipes in c book it is about orders of magnitude slower than the outerbridge karn gillogly et al implementation it may be instructional but it isn t very fast grady netcom com ef e ad d d c f fc ac f d f e f
