DES

• 64-bit block, 56-bit key
  • Key standard is 64bit, 8 bits for parity not keying
• Five modes of operation
  • ECB - Electronic Code Book
  • CBC - Cipher Block Chaining
  • CFB - Cipher Feedback
  • OFB - Output Feedback
  • CTR - Counter
• 64bits of plaintext generate 64bits of ciphertext

DES - Electronic Code Book Mode

DES - CBC - Cipher Bock Chaining Mode

DES - CFB - Cipher Feedback Mode

DES - OFB - Output Feedback Mode

DES - CTR - Counter Mode

3DES

DES-EEE3

E(
  K1, E(
    K2, E(
      K3, P)))

DES-EDE3

E(
  K1, D(
    K2, E(
      K3, P)))

DES-EEE2

E(
  K1, E(
    K2, E(
      K1, P)))

DES-EDE2

E(
  K1, D(
    K2, E(
      K1, P)))

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