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CCA Release 2.54
┌──────────────┬──────────────┬──────────────┐ ┌──────────────┬──────────────┐
│ Master Key │ │ Control Vector │
└────│─────────┴────│─────────┴────│─────────┘ └────│─────────┴─────────│────┘
│ 7 8 │ 15 16 │ 23 │ 7 8 │ 15
│ ┌─────────│────┬─────────│────┬──────────────┤ │
├──┐ │ ├──┐ │ ├──┐ │ │ │
│ │ │ │ │
│ ┌───┐ │ ┌───┐ │ ┌───┐ │ │
│ │XOR│ │ │XOR│ │ │XOR│ │ │
│ └─┬─┘ │ └─┬─┘ │ └─┬─┘ │ │
│ │ │ │ │
│K1 │K2 │K3 │ │
│ ┌─────────│────┬─────────│────┬──────────────│───────────────────┤
└──┐ │ └──┐ │ └──┐ │ │ │
│ │
┌───┐ ┌───┐ ┌───┐ │ │
│XOR│ │XOR│ │XOR│ │ │
└─┬─┘ └─┬─┘ └─┬─┘ │ │
│ │
K4 K5 K6 │ │
││
┌──────────────┬──────────────┐ │ │
│ Key-Encrypting Key │ │ │
└────│─────────┴────│─────────┘ │ │
│ 7 8 │ 15 │ │
│ ┌─────────│────┬─────────────────────────────┘ │
├──┐ │ ├──┐ │ │
│ │ │
│ ┌───┐ │ ┌───┐ │
│ │XOR│ │ │XOR│ │
│ └─┬─┘ │ └─┬─┘ │
│ │ │
│ K1,K3 │ K2 │
│ ┌─────────│────┬─────────────────────────────────────────────────┘
└──┐ │ └──┐ │
┌───┐ ┌───┐
│XOR│ │XOR│
└─┬─┘ └─┬─┘
K4,K6 K5
Multiple Multiple
Encipherment Decipherment
┌───────────┬───────────┐ ┌───────────┬───────────┐
│ Clear Key │ │Multiply-Enciphered Key│
└────┬──────┴──────┬────┘ └────┬──────┴──────┬────┘
│ 7 8 │ 15 │ 7 8 │ 15
┌─────┐ ┌─────┐ ┌─────┐ ┌─────┐
K1──│Encode│ │Encode│──K4 K3──│Decode│ │Decode│──K6
└──┬───┘ └───┬──┘ └──┬───┘ └───┬──┘
┌─────┐ ┌─────┐ ┌─────┐ ┌─────┐
K2──│Decode│ │Decode│──K5 K2──│Encode│ │Encode│──K5
└──┬───┘ └───┬──┘ └──┬───┘ └───┬──┘
┌─────┐ ┌─────┐ ┌─────┐ ┌─────┐
K3──│Encode│ │Encode│──K6 K1──│Decode│ │Decode│──K4
└──┬───┘ └───┬──┘ └──┬───┘ └───┬──┘
┌──────────┬──────────┐ ┌──────────┬──────────┐
│Multiply-Enciphered Key│ │ Clear Key │
└───────────┴───────────┘ └───────────┴───────────┘
Figure C-4. Multiply-Enciphering and Multiply-Deciphering CCA Keys
Notes:
1. The encode and decode processes are the DES Electronic Code Book (ECB)
processes for ciphering 64 data bits using a single-length key, K
n
.
2. A CCA cryptographic implementation processes a single-length key in the same
way as it processes the left half of a double-length key.
3. If the left and right halves of a double-length key-encrypting key have the same
value, using the key in multiple-encipherment or multiple-decipherment of a key
is equal to single-encipherment or single-decipherment of a key.
4. The control vector for a double-length key consists of two halves. The second
half is the same as the first half except for bits 41 and 42, which are reversed
in value.
Appendix C. CCA Control-Vector Definitions and Key Encryption C-13