1. Schneier, B., 1996. Applied Cryptography, 2nd edition, John Wiley & Sons Inc, 1996.
2. Menezes, A.J., van Oorschot, P.C. and Vanstone, S.A., 1997. Handbook of Applied Cryptography, CRC Press, 1997.
3. ANSI X3.92. American National Standard — Data Encryption Algorithm, American National Standards Institute, 1981.