“The National Institute of Standards and Technology (NIST)
officially announced that from among the five finalist candidate
algorithms, Rijndael, designed by Joan Daemen and Vincent Rijmen,
would be the new Advanced Encryption Standard.”
“Rijndael is not a Feistel cipher like DES.“
“In DES and other Feistel ciphers, in each round one half of the
block is subjected to a function which involves subkey material,
which needs to be nonlinear and which may not be (and in fact, is
not in DES) invertible. The round as a whole is guaranteed to be
invertible, however, since the half of the block subjected to that
function is not changed. Instead, the other half of the block is
changed, by being subjected to an XOR operation with the output of
that function.”