module Crypt_3des:DES, created by the NSA, is a 64 bit block cipher. Triple-DES is a variant that applies DES three times to the same input block. More precisely, first the block is encrypted with key k1, then decrypted with key k2 and then encrypted again with key k3. It is best to choose k1,k2,k3 distinct. Sometimes k1=k3. This implementation accepts strings with 8, 16, or 24 bytes as keys, taking the first 8 bytes as k1, the second as k2, and the third as k3. Please note that some bits are used as parity bits, such that the effective key length is 56, resp. 112, resp. 168 bits.sig
..end
Triple-DES is 3 times slower than DES.
module Cryptsystem:Cryptsystem_64.T
module Cryptmodes:Cryptmodes_64.T
with type key = Cryptsystem.key
Although only 56 bits count a DES key is written with 64 bits. The
extra bits are used for parity checking.
val check_parity : string -> unit
val set_parity : string -> string