Figure 205. Des/Tdes-Cbc Mode Encryption - ST STM32F40 Series Reference Manual

Cryptographic processor (CRYP)

Figure 205. DES/TDES-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.
555/1422
DATATYPE
AHB2 data write
(before CRYP
is enabled)
IV0(L/R)
K1
O is written back
into IV at the
K2
same time as it
is pushed into
the OUT FIFO
K3
DATATYPE
Doc ID 018909 Rev 4
IN FIFO
plaintext P
P, 64 bits
swapping
Ps, 64 bits
64
+
I, 64 bits
64
DEA, encrypt
64
DEA, decrypt
64
DEA, encrypt
O, 64 bits
swapping
C, 64 bits
OUT FIFO
ciphertext C
RM0090
ai16070b