AES Registers
www.ti.com
644
SWRU543–January 2019
Submit Documentation Feedback
Copyright © 2019, Texas Instruments Incorporated
Advance Encryption Standard Accelerator (AES)
Table 17-24. AES_CTRL Register Field Descriptions (continued)
Bit Field Type Reset Description
17-16 GCM R/W 0h
AES-GCM mode is selected; this is a combined mode, using the
Galois field multiplier GF(2
128
) for authentication and AES-CTR mode
for encryption, the bits specify the GCM mode.
0h = No operation
1h = GHASH with H loaded and Y0-encrypted forced to zero
2h = GHASH with H loaded and Y0-encrypted calculated internally
3h = Autonomous GHASH (both H and Y0-encrypted calculated
internally)
15 CBCMAC R/W 0h
AES-CBC MAC is selected; the Direction bit must be set to 1 for this
mode.
0h = Other mode selected
1h = CBCMAC mode selected
14 F9 R/W 0h
AES f9 mode is selected; the AES key size must be set to 128-bit for
this mode.
0h = Other mode selected
1h = f9 selected
13 F8 R/W 0h
AES f8 mode is selected; the AES key size must be set to 128-bit for
this mode.
0h = Other mode selected
1h = f8 selected
12-11 XTS R/W 0h
AES-XTS operation is selected; the bits specify the XTS mode.
0h = No operation
1h = Previous/intermediate tweak value and j loaded (value is loaded
through IV, j is loaded through the AAD length register)
2h = Key2, i and j loaded (i is loaded through IV, j is loaded through
the AAD length register)
3h = Key2 and i loaded, j=0 (i is loaded through IV)
10 CFB R/W 0h
Full block AES cipher feedback mode (CFB128) is selected.
0h = Other mode selected
1h = CFB selected
9 ICM R/W 0h
AES integer counter mode (ICM) is selected, this is a counter mode
with a 16-bit wide counter.
0h = Other mode selected
1h = ICM mode selected
8-7 CTR_WIDTH R/W 0h
Specifies the counter width for AES-CTR mode
0h = Counter is 32 bits
1h = Counter is 64 bits
2h = Counter is 128 bits
3h = Counter is 192 bits
6 CTR R/W 0h
This bit must also be set for GCM and CCM, when encryption or
decryption is required.
0h = Other mode selected
1h = Counter mode
5 MODE R/W 0h
ECB/CBC mode
0h = ECB mode
1h = CBC mode
4-3 KEY_SIZE R/W 0h
Key Size
0h = Reserved
1h = Key is 128 bits
2h = Key is 192 bits
3h = Key is 256
To Next Page
Loading...
