NewDES

NewDES is a symmetric key block cipher created in 1984 and 1985 by Robert Scott as a possible replacement for the Data Encryption Standard. Despite the name it is not derived from DES and has a quite different structure. It has no bit-level permutations, which makes it easy to implement in software, because every operation is performed on whole bytes. It is a product cipher of 17 rounds working on a 64-bit data block with a 120-bit key. In each round subkey material is combined by XOR with one-byte sub-blocks of the data and passed through an S-box, which is itself derived from the text of the United States Declaration of Independence as a nothing-up-my-sleeve number. Scott published the design in Cryptologia in January 1985. The cipher was revised in 1996 with a modified key schedule to counter a related-key attack, and that version is sometimes called NewDES-96. Cryptanalysis has been limited: it shares DES complementation property, Eli Biham found a related-key attack needing 2 to the 33 chosen-key chosen plaintexts, and John Kelsey, Bruce Schneier and David Wagner developed another related-key attack, so NewDES is considered less secure than DES. AES has since filled its intended niche.