title: E2 (cipher)
text: # E2 (cipher)
  
  In cryptography, E2 is a symmetric block cipher which was created in 1998 by NTT and submitted to the AES 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-round Feistel network. E2 has an input transformation and output transformation that both use modular multiplication, but the round function itself consists only of XORs and S-box lookups. The single 8×8-bit S-box is constructed from the composition of an affine transformation with the discrete exponentiation $x^{127}$ over the finite field $GF(2^8).$ NTT adopted many of E2's special characteristics in Camellia, which has essentially replaced E2.
  
  