Triple DES

• 1998: Electronic Frontier Foundation built Deep Crack

  • $220,000 machine cracked 56-bit key in ~56 hours
    • 27 PCBs
    • 64 chips/PCB
    • Tested 9×1010 keys/second

• Solution: Triple DES

  • DES with two 56-bit keys
    • Key space is 2112
  • Key1 DES-encrypts
  • Key2 DES-decrypts the encryption
    • The wrong key, so scrambles the data
  • Key1 encrypts again

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