(or Data Encryption Standard), a (symmetric) block cipher using a 64 bit block size, with keys of size 56 bit, the standard US block cipher from 1976 to 2001.

learn more… | top users | synonyms

19
votes
2answers
3k views

How were the DES S-box values determined?

It seems like the S-boxes in DES have essentially random values. How were these chosen?
33
votes
3answers
5k views

What are the benefits of the two permutation tables in DES?

Why do we use a permutation table in the first step of DES algorithm and one at the end of algorithm?