AES Performance Information
673
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Advance Encryption Standard Accelerator (AES)
Table 9-3. AES Module Performance (Input/Output Block Size = 128) (continued)
Key Size
Mode of Operation
Cycles per
Block
(1)
Throughput
(Bits per
Cycle)
(3)
Numbers for regular CCM mode. Dependent on the AAD length it is possible that one additional encryption needs to be done to
finalize the AAD authentication; if the additional operation is required, this number needs to be doubled.
256
ECB encrypt or decrypt
44
2.91
CBC-decrypt
CTR/ICM encrypt or decrypt
CFB128-decrypt
CBC encrypt
45
2.84
OFB encrypt or decrypt
f8 encrypt or decrypt
CFB128 encrypt
XTS encrypt or decrypt
GCM-outbound inbound
CCM encrypt or decrypt
90
1.42
CBC-MAC
(3)
45
2.84
f9
(3)
The Cycles per Block numbers do not apply to the first block after selection of a new key or mode of
operation, or the last block before switching to a new algorithm.
indicates the additional clock
cycles required for changing context data.
(1)
Numbers for regular GCM mode (H is precalculated and Y0-encrypted need to be calculated internally using the new IV). If H
needs to be calculated by the core (complete GCM mode), this number needs to be doubled. If Y0-encrypted is not calculated
(forced to zero, such that the hash result is not encrypted) this number is zero.
(2)
Numbers for regular CCM mode. Dependent on the AAD length it is possible that one additional encryption needs to be done to
finalize the AAD authentication; if the additional operation is required, this number needs to be doubled.
Table 9-4. AES Module Packet Mode Switch Overhead
Title
Cycles Needed For First Block /
To Finish Last Block
Total
Mode is encrypt
1 / 1
2
Mode is decrypt, key size is 128
32 / 1
33
Mode is decrypt, key size is 192
38 / 1
39
Mode is decrypt, key size is 256
44 / 1
45
Mode is XTS, key size is 128
34 / 1
35
Mode is XTS, key size is 192
40 / 1
41
Mode is XTS, key size is 256
46 / 1
47
Outbound GCM, AES key size is 128
33
(1)
/ 52
85
Outbound GCM, AES key size is 192
39
(1)
/ 52
91
Outbound GCM, AES key size is 256
45
(1)
/ 52
97
Inbound GCM, AES key size is 128
33
(1)
/ 27
60
Inbound GCM, AES key size is 192
39
(1)
/ 27
66
Inbound GCM, AES key size is 256
45
(1)
/ 27
72
Outbound CCM, AES key size is 128
33
(1)
/ 33
66
Outbound CCM, AES key size is 192
39
(2)
/ 39
78
Outbound CCM, AES key size is 256
45
(2)
/ 45
90
Inbound CCM, AES key size is 128
33
(2)
/ 33
66
Inbound CCM, AES key size is 192
39
(2)
/ 39
78
Inbound CCM, AES key size is 256
45
(2)
/ 45
90