GD32W51x User Manual
927
Figure 27-2. DATAM Byte swapping and Bit swapping
Byte swapping
A3
A2
A1
A0
B3
B2
B1
B0
C3
C2
C1
C0
D3
D2
D1
D0
A0
A1
A2
A3
B0
B1
B2
B3
C0
C1
C2
C3
D0
D1
D2
D3
WORD 0 (MSB)
Bit swapping
A31
...
A1
A0
B31
...
B1
B0
C31
...
C1
C0
D31
...
D1
D0
A0
A1
...
A31
B0
B1
...
B31
C0
C1
...
C31
D0
D1
...
D31
WORD 1
WORD 2
WORD 3 (LSB)
WORD 0 (MSB)
WORD 1
WORD 2
WORD 3 (LSB)
27.3.2.
Initialization vectors
The initialization vectors are used in CBC, CTR, GCM, GMAC, CCM, CFB and OFB modes
to XOR with data blocks. They are independent of plaintext and ciphertext, and the DATAM
value will not affect them. Note the initialization vector registers CAU_IV0,1(H/L) can only be
written when BUSY is 0, otherwise the write operations are invalid.
27.4.
Cryptographic acceleration processor
The cryptographic acceleration unit implements DES and AES acceleration processors,
which are detailed described in section
DES/TDES cryptographic acceleration processor
AES cryptographic acceleration processor
shows the block diagram of the cryptographic acceleration unit.