Conventional Cryptography - A Classical Introduction to Cryptography: Applications for Communications Security - page 42

y l y r y l y r

P P

M − 1

⊕

k r

⊕

ϕ

k r

⊕ ⊕

k l

ROTL

k l ⊕ ⊕

x l x r

x l x r

Figure 2.28. The invert mixing box of CSC.

For completeness we also provide a complete view of CSC in Fig. 2.29. We see
that the key schedule is actually defined by a Feistel scheme.

2.7 The Advanced Encryption Standard (AES)

With the improvement of computer technology due to the Moore law, the security of
DES is no longer appropriate for electronic commerce. The US Government decided
to restart a standardization process called the Advanced Encryption Standard (AES)

k − 1 k − 2

x

c 0

F

k 0

E ⊕

c 1

k 1 F

E ⊕

c 2

F

k 2

E ⊕

c 3

F

k 3

E ⊕

c 4

F

k 4

E ⊕

c 5

k 5 F

E ⊕

c 6

k 6 F

E ⊕

c 7

F

k 7

E ⊕

c 8

k 8

F

⊕

⊕

y

Figure 2.29. External view of CSC.