1. National Bureau of Standards Special Publication, Computer security and the Data Encryption Standard‘The Data Encryption Standard in Perspective’, , February, 1978 DAVIES, R.M.
2. National Bureau of Standards, Federal Information Processing Standards Publication‘Guidelines for implementing and using the NBS Encryption Standard’, 74, April, 1984
3. National Bureau of Standards, Federal Information Processing Standards Publication‘Data Encryption Standard’, 46, January, 1977 Published by the
4. National Bureau of Standards, Federal Information Processing Standards Publication‘DES Modes of operation’, 81, December, 1980