| General | |
|---|---|
| Designers | NTT |
| First published | 1998 |
| Successors | Camellia |
| Cipher detail | |
| Key sizes | 128, 192, or 256 bits |
| Block sizes | 128 bits |
| Structure | Feistel network |
| Rounds | 12 |
Incryptography,E2 is asymmetricblock cipher which was created in 1998 byNTT and submitted to theAES competition.
Like other AES candidates, E2 operates on blocks of 128 bits, using a key of 128, 192, or 256 bits. It uses a 12-roundFeistel network. E2 has an input transformation and output transformation that both usemodular multiplication, but the round function itself consists only ofXORs andS-box lookups. The single 8×8-bit S-box is constructed from the composition of anaffine transformation with the discreteexponentiation x127 over thefinite field GF(28). NTT adopted many of E2's special characteristics inCamellia, which has essentially replaced E2.