ST STM32L4+ Series Reference Manual page 1180

Public key accelerator (PKA) applied to STM32L4P5xx and STM32L4Q5xx only
These values allow the recipient to compute the exponentiation m = A
efficiently as follows:
•
m = A
1
•
m = A
2
•
h = q
•
m = m
Operation instructions for computing CRT exponentiation A
Table 255.
Parameters with direction
IN
IN
IN
IN
OUT
1. Must be different from 2.
36.4.14 Point on elliptic curve Fp check
This operation consists in checking whether a given point P (x, y) satisfies or not the curves
over prime fields equation y
curve.
Operation instructions for point on elliptic curve Fp check are summarized in
1180/2301
dP
mod p
dQ
mod p
(m - m ) mod p, with m
inv 1 2
+ hq
2
Table 255. CRT exponentiation
MODE 0x07
Operand length (in bits, not null)
Operand d (0 ≤ d
P
Operand d (0 ≤ d
Q
Operand q (0 ≤ q
inv
(1)
Prime p (0 ≤ p < 2
(1)
Prime q (0 ≤ q< 2
Operand A (0 ≤ A< 2
d
Result: A mod pq (0 ≤ result < pq)
2
= (x
> m
1 2
Value (Note)
M/2
< 2 )
P
M/2
< 2 )
Q
M/2
< 2 )
inv
M/2
)
M/2
)
M/2
)
3
+ ax + b) mod p, where a and b are elements of the
RM0432 Rev 6
d
(mod pq) more
d
mod pq are summarized in
Storage
PKA_CR
RAM@0x404
RAM@0x65C
RAM@0xBD0
RAM@0x7EC
RAM@0x97C
RAM@0xD5C
RAM@0xEEC
RAM@0x724
Table
RM0432
Size
6 bits
32 bits
ROS/2
ROS
256.