Table 144. Pka Integer Arithmetic Functions List; Table 145. Pka Prime Field (Fp) Elliptic Curve Functions List - STMicroelectronics STM32WL5 Series Reference Manual

RM0453
PKA operating modes
The list of operations the PKA can perform is detailed in
respectively, for integer arithmetic functions and prime field (Fp) elliptic curve functions.
Each of these operating modes has an associated code that has to be written to the MODE
field in the PKA_CR register.
PKA_CR.MODE[5:0]
Hex
0x01
0x0E
0x0F
0x10
0x00
0x02
0x08
0x0D
0x09
0x0A
0x0B
0x0C
0x07
PKA_CR.MODE[5:0]
Hex
0x28
0x20
0x22
0x24
0x26
Montgomery space and fast mode operations
For efficiency reason the PKA internally performs modular multiply operations in the
Montgomery domain, automatically performing inward and outward transformations.
As Montgomery parameter computation is time consuming the application can decide to use
a faster mode of operation, during which the precomputed Montgomery parameter is

Table 144. PKA integer arithmetic functions list

Binary
000001 Montgomery parameter computation R2 mod n
001110 Modular addition (A+B) mod n
001111 Modular subtraction (A-B) mod n
010000 Montgomery multiplication (AxB) mod n
000000 Modular exponentiation A
000010 Modular exponentiation A
001000 Modular inversion A-1 mod n
001101 Modular reduction A mod n
001001 Arithmetic addition A+B
001010 Arithmetic subtraction A-B
001011 Arithmetic multiplication AxB
001100 Arithmetic comparison (A=B, A>B, A<B)
000111 RSA CRT exponentiation

Table 145. PKA prime field (Fp) elliptic curve functions list

Binary
101000 Point on elliptic curve Fp check
100000 ECC scalar multiplication kP
100010 ECC scalar multiplication kP (fast mode)
100100 ECDSA sign
100110 ECDSA verification
RM0453 Rev 5
Table 144
Performed operation
e
mod n
e
mod n (fast mode)
Performed operation
Public key accelerator (PKA)
and Table 145,
Reference
Section 24.4.2
Section 24.4.3
Section 24.4.4
Section 24.4.5
Section 24.4.6
Section 24.4.7
Section 24.4.8
Section 24.4.9
Section 24.4.10
Section 24.4.11
Section 24.4.12
Section 24.4.13
Reference
Section 24.4.14
Section 24.4.15
Section 24.4.16
Section 24.4.17
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