Table 156. Arithmetic Multiplication; Table 157. Arithmetic Comparison - STMicroelectronics STM32WL5 Series Reference Manual

RM0453
24.4.11 Arithmetic multiplication
Arithmetic multiplication operation consists in the computation of AxB. Operation
instructions are summarized in
Parameters with direction
IN
OUT
24.4.12 Arithmetic comparison
Arithmetic comparison operation consists in the following computation:
•
If A=B then result=0x0
• If A>B then result=0x1
•
If A<B then result=0x2
Operation instructions for arithmetic comparison are summarized in
Parameters with direction
IN
OUT
24.4.13 RSA CRT exponentiation
For efficiency many popular crypto libraries like OpenSSL RSA use the following
optimization for decryption and signing based on the Chinese remainder theorem (CRT):
• p and q are precomputed primes, stored as part of the private key
•
d = d mod (p -1)
P
•
d = d mod (q -1) and
Q
•
q = q
inv
Table

Table 156. Arithmetic multiplication

MODE 0x0B
Operand length M (In bits, not null)
Operand A (0 ≤ < A < 2
Operand B (0 ≤ < B < 2
Result: AxB (0 ≤ result < 2

Table 157. Arithmetic comparison

MODE
Operand length M
Operand A
Operand B
Result A=B or A>B or A<B 0x0, 0x1 or 0x02
-1
mod p
156.
Value (Note)
M
)
M
)
M
)
Value (Note)
0x0C
(In bits, not null)
M
(0 ≤ < A < 2 )
M
(0 ≤ < B < 2 )
RM0453 Rev 5
Public key accelerator (PKA)
Storage
PKA_CR
RAM@0x404
RAM@0x8B4
RAM@0xA44
RAM@0xBD0 2xROS
Table 157.
Storage
PKA_CR
RAM@0x404
RAM@0x8B4
RAM@0xA44
RAM@0xBD0
Size
6 bits
32 bits
ROS
Size
6 bits
32 bits
ROS
32 bits
707/1450
720