Serpent (cipher)
Serpent has a block size of 128 bits and supports a key size of 128, 192 or 256 bits. The cipher is a 32-round substitution-permutation network operating on a block of four 32-bit words.  Each round applies one of eight 4-bit by 4-bit S-boxes 32 times in parallel. Serpent was designed so that all operations can be executed in parallel, using 32 1-bit slices.  This maximizes parallelism, but also allows use of the extensive cryptanalysis work performed on DES.