
Public key accelerator (PKA)
RM0453
696/1454
RM0453 Rev 2
24
Public key accelerator (PKA)
24.1 Introduction
PKA (public key accelerator) is intended for the computation of cryptographic public key
primitives, specifically those related to RSA, Diffie-Hellmann or ECC (elliptic curve
cryptography) over GF(
p
) (Galois fields). To achieve high performance at a reasonable cost,
these operations are executed in the Montgomery domain.
All needed computations are performed within the accelerator, so no further
hardware/software elaboration is needed to process the inputs or the outputs.
24.2 PKA
main
features
•
Acceleration of RSA, DH and ECC over GF(
p
) operations, based on the Montgomery
method for fast modular multiplications. More specifically:
–
RSA modular exponentiation, RSA Chinese Remainder Theorem (CRT)
exponentiation
–
ECC scalar multiplication, point on curve check
–
ECDSA signature generation and verification
•
Capability to handle operands up to 3136 bits for RSA/DH and 640 bits for ECC.
•
Arithmetic and modular operations such as addition, subtraction, multiplication,
modular reduction, modular inversion, comparison, and Montgomery multiplication.
•
Built-in Montgomery domain inward and outward transformations.
•
AMBA AHB slave peripheral, accessible through 32-bit word single accesses only
(otherwise, for writes, an AHB bus error is generated, and write accesses are ignored).
24.3 PKA
functional
description
24.3.1
PKA block diagram