psa_kat_shim.c File Reference

TEST-ONLY platform shims for the tf-psa-crypto software backend. More...

#include <stddef.h>
#include <stdint.h>
#include "mbedtls/platform_util.h"
#include "psa/crypto.h"

Include dependency graph for psa_kat_shim.c:

Go to the source code of this file.

Enumerations
enum	shim_const_t : uint32_t {   k_shim_lcg_mul = 1664525U ,   k_shim_lcg_add = 1013904223U ,   k_shim_seed = 0x1234ABCDU ,   k_shim_top_shift = 24U }
	LCG multiplier (Numerical Recipes) for the deterministic test RNG. More...

Functions
psa_status_t	mbedtls_psa_external_get_random (mbedtls_psa_external_random_context_t *context, uint8_t *output, size_t output_size, size_t *output_length)

Detailed Description

TEST-ONLY platform shims for the tf-psa-crypto software backend.

Tag

[Ring 6 / APP] {World: S}

The vendored tf-psa-crypto port config enables MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG, so psa_crypto_init needs an external RNG entry point, and (if MBEDTLS_HAVE_TIME is set) an mbedtls_ms_time. This app is a known-answer test whose operations – SHA-256, AES-128-GCM with a fixed nonce, and ECDSA-P256 verify – draw NO randomness, so a deterministic RNG here does not affect the KAT result. It exists only so psa_crypto_init succeeds.

Warning

NOT cryptographically secure. This deterministic RNG must never ship in a real image; a production build needs a real entropy source (see libs/ra8_hal/src/ra8_rsip.c – the RSIP TRNG needs an FSP port).

Copyright

Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since

0.1.0

Definition in file psa_kat_shim.c.

Enumeration Type Documentation

shim_const_t

enum shim_const_t : uint32_t

LCG multiplier (Numerical Recipes) for the deterministic test RNG.

Enumerator
k_shim_lcg_mul	Shim lcg mul.
k_shim_lcg_add	Shim lcg add.
k_shim_seed	Shim seed.
k_shim_top_shift	Shim top shift.

Definition at line 32 of file psa_kat_shim.c.

Function Documentation

mbedtls_psa_external_get_random()

psa_status_t mbedtls_psa_external_get_random	(	mbedtls_psa_external_random_context_t *	context,
		uint8_t *	output,
		size_t	output_size,
		size_t *	output_length )

Definition at line 39 of file psa_kat_shim.c.

References k_shim_lcg_add, k_shim_lcg_mul, k_shim_seed, and k_shim_top_shift.