Cryptographic processor (CRYP)
RM0090
722/1731
DocID018909 Rev 11
block of data.) The AES-CBC decryption process continues in this manner until the last
complete ciphertext block has been decrypted. Ciphertext representing a partial data
block must be decrypted in a manner specified for the application.
Figure 224. AES-CBC mode encryption
1. K: key; C: cipher text; I: input block; O: output block; Ps: plain text before swapping (when decoding) or
after swapping (when encoding); P: plain text; IV: Initialization vectors.
2. IVx=[IVxR IVxL], R=right, L=left.
3. If Key size = 128 => Key = [K3 K2].
If Key size = 192 => Key = [K3 K2 K1]
If Key size = 256 => Key = [K3 K2 K1 K0].
).&)&/
!%!ENCRYPT
0BITS
/54&)&/
/BITS
PLAINTEXT0
CIPHERTEXT#
SWAPPING
)6;)6)6=
)BITS
!(" DATAWRITE
BEFORE#290
ISENABLED
/ISWRITTEN
BACKINTO)6
ATTHESAMETIME
ASITISPUSHED
INTOTHE/54&)&/
SWAPPING
#BITS
$!4!490%
$!4!490%
+
OR
0SBITS
AIB