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pqcrypto/test/common/nistkatrng.c
Thom Wiggers 65a6a63e08
Put all common primitives on the heap (#266)
* Put AES ctx on the heap

This forces people to use the ``ctx_release`` functions, because otherwise there will be leaks

* Put fips202 on the heap

* Add much more docs for fips202.h

* fixup! Put fips202 on the heap

* Put SHA2 on the heap-supporting API

* Fix clang-tidy warnings

* Fix unreachable free() in falcon

* Fix McEliece8192128f-sse GNU Makefile
2020-02-11 11:15:14 +01:00

105 lines
2.8 KiB
C

//
// rng.c
//
// Created by Bassham, Lawrence E (Fed) on 8/29/17.
// Copyright © 2017 Bassham, Lawrence E (Fed). All rights reserved.
// Modified for liboqs by Douglas Stebila
//
#include <assert.h>
#include <string.h>
#include "aes.h"
#include "randombytes.h"
typedef struct {
uint8_t Key[32];
uint8_t V[16];
int reseed_counter;
} AES256_CTR_DRBG_struct;
static AES256_CTR_DRBG_struct DRBG_ctx;
static void AES256_CTR_DRBG_Update(const uint8_t *provided_data, uint8_t *Key, uint8_t *V);
// Use whatever AES implementation you have. This uses AES from openSSL library
// key - 256-bit AES key
// ctr - a 128-bit plaintext value
// buffer - a 128-bit ciphertext value
static void AES256_ECB(uint8_t *key, uint8_t *ctr, uint8_t *buffer) {
aes256ctx ctx;
aes256_keyexp(&ctx, key);
aes256_ecb(buffer, ctr, 1, &ctx);
aes256_ctx_release(&ctx);
}
void nist_kat_init(uint8_t *entropy_input, const uint8_t *personalization_string, int security_strength);
void nist_kat_init(uint8_t *entropy_input, const uint8_t *personalization_string, int security_strength) {
uint8_t seed_material[48];
assert(security_strength == 256);
memcpy(seed_material, entropy_input, 48);
if (personalization_string) {
for (int i = 0; i < 48; i++) {
seed_material[i] ^= personalization_string[i];
}
}
memset(DRBG_ctx.Key, 0x00, 32);
memset(DRBG_ctx.V, 0x00, 16);
AES256_CTR_DRBG_Update(seed_material, DRBG_ctx.Key, DRBG_ctx.V);
DRBG_ctx.reseed_counter = 1;
}
int randombytes(uint8_t *buf, size_t xlen) {
uint8_t block[16];
int i = 0;
while (xlen > 0) {
//increment V
for (int j = 15; j >= 0; j--) {
if (DRBG_ctx.V[j] == 0xff) {
DRBG_ctx.V[j] = 0x00;
} else {
DRBG_ctx.V[j]++;
break;
}
}
AES256_ECB(DRBG_ctx.Key, DRBG_ctx.V, block);
if (xlen > 15) {
memcpy(buf + i, block, 16);
i += 16;
xlen -= 16;
} else {
memcpy(buf + i, block, xlen);
xlen = 0;
}
}
AES256_CTR_DRBG_Update(NULL, DRBG_ctx.Key, DRBG_ctx.V);
DRBG_ctx.reseed_counter++;
return 0;
}
static void AES256_CTR_DRBG_Update(const uint8_t *provided_data, uint8_t *Key, uint8_t *V) {
uint8_t temp[48];
for (int i = 0; i < 3; i++) {
//increment V
for (int j = 15; j >= 0; j--) {
if (V[j] == 0xff) {
V[j] = 0x00;
} else {
V[j]++;
break;
}
}
AES256_ECB(Key, V, temp + 16 * i);
}
if (provided_data != NULL) {
for (int i = 0; i < 48; i++) {
temp[i] ^= provided_data[i];
}
}
memcpy(Key, temp, 32);
memcpy(V, temp + 32, 16);
}