
AES hardware accelerator (AES)
RM0453
684/1454
RM0453 Rev 2
23.6
AES processing latency
The tables below summarize the latency to process a 128-bit block for each mode of
operation.
23.7 AES
registers
23.7.1
AES control register (AES_CR)
Address offset: 0x00
Reset value: 0x0000 0000
Table 140. Processing latency for ECB, CBC and CTR
Key size
Mode of operation
Algorithm
Clock
cycles
128-bit
Mode 1: Encryption
ECB, CBC, CTR
51
Mode 2: Key derivation
-
59
Mode 3: Decryption
ECB, CBC, CTR
51
256-bit
Mode 1: Encryption
ECB, CBC, CTR
75
Mode 2: Key derivation
-
82
Mode 3: Decryption
ECB, CBC, CTR
75
Table 141. Processing latency for GCM and CCM (in clock cycles)
Key size
Mode of operation
Algorithm
Init Phase
Header
phase
(1)
Payload
phase
Tag phase
128-bit
Mode 1: Encryption/
Mode 3: Decryption
GCM
64
35
51
59
CCM
63
55
114
58
256-bit
Mode 1: Encryption/
Mode 3: Decryption
GCM
88
35
75
75
CCM
87
79
162
82
1. Data insertion can include wait states forced by AES on the AHB bus (maximum 3 cycles, typical 1 cycle).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
NPBLB[3:0]
Res.
KEYS
IZE
Res.
CHMOD[2]
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res.
GCMPH[1:0]
DMAOUTEN
DMAINEN
ERRIE CCFIE
ERRC
CCFC
CHMOD[1:0]
MODE[1:0]
DATATYPE[1:0]
EN
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits 31:24 Reserved, must be kept at reset value.