In Cryptography, a block cipher is a keyed permutation from N-bit blocks to N-bit blocks.

Modes of operation

Electronic Code Book (ECB)

  • Use the key with the block cipher to get your N-bit to N-bit permutation.
  • Go over the plaintext in blocks, encrypt each block using the raw block cipher.
  • There is no IV. With the same key, the same N-bit block always encrypts to the same ciphertext.