Serpent can be sped up greatly by replacing S-box substitution with a sequence of binary operations, and the optimal implementation depends upon finding cyrpto fastest then one of eight S-boxes reproduce this substitution simple linear transformation is done.
This is done in order to make short keys map to long keys of bits, one "1" bit is appended to the end of the short key followed by "0" bits until the short key is mapped to a long key length. Symmetric ciphers are basic blocks of many cryptography systems and are often used with other cryptography mechanisms that compensate their shortcomings. Registered users have higher Daily Credits amounts and can even increase them by purchasing subscriptions.
