References
B. Schneier, “Applied Cryptography”, 2nd Edition, Wiley 1996
A. Menezes, P. Van Oorschot (Editor), Scott A. Vanstone (Editor), “Handbook of Applied Cryptography”, CRC Press Series on Discrete Mathematics and Its Applications, 1996
http://www.eff.org/descracker.html
J. Gilmore (Editor), “Cracking DES: Secrets of Encryption Research, Wiretap Politics & Chip Design”, Electronic Frontier Foundation, 1998