RRG-Proxmark3/client/deps/amiitool/keygen.c
iceman1001 414275802d style
2024-01-25 01:55:07 +01:00

55 lines
1.8 KiB
C

/*
* (c) 2015-2017 Marcos Del Sol Vives
*
* SPDX-License-Identifier: MIT
*/
#include "drbg.h"
#include "keygen.h"
#include <assert.h>
#include <stdio.h>
#include <string.h>
static void nfc3d_keygen_prepare_seed(const nfc3d_keygen_masterkeys_t *baseKeys, const uint8_t *baseSeed, uint8_t *output, size_t *outputSize) {
assert(baseKeys != NULL);
assert(baseSeed != NULL);
assert(output != NULL);
assert(outputSize != NULL);
uint8_t *start = output;
// 1: Copy whole type string
// output = (uint8_t *)strcpy((char *)output, baseKeys->typeString);
output = memccpy(output, baseKeys->typeString, '\0', sizeof(baseKeys->typeString));
// 2: Append (16 - magicBytesSize) from the input seed
size_t leadingSeedBytes = 16 - baseKeys->magicBytesSize;
memcpy(output, baseSeed, leadingSeedBytes);
output += leadingSeedBytes;
// 3: Append all bytes from magicBytes
memcpy(output, baseKeys->magicBytes, baseKeys->magicBytesSize);
output += baseKeys->magicBytesSize;
// 4: Append bytes 0x10-0x1F from input seed
memcpy(output, baseSeed + 0x10, 16);
output += 16;
// 5: Xor last bytes 0x20-0x3F of input seed with AES XOR pad and append them
unsigned int i;
for (i = 0; i < 32; i++) {
output[i] = baseSeed[i + 32] ^ baseKeys->xorPad[i];
}
output += 32;
*outputSize = output - start;
}
void nfc3d_keygen(const nfc3d_keygen_masterkeys_t *baseKeys, const uint8_t *baseSeed, nfc3d_keygen_derivedkeys_t *derivedKeys) {
uint8_t preparedSeed[NFC3D_DRBG_MAX_SEED_SIZE];
size_t preparedSeedSize;
nfc3d_keygen_prepare_seed(baseKeys, baseSeed, preparedSeed, &preparedSeedSize);
nfc3d_drbg_generate_bytes(baseKeys->hmacKey, sizeof(baseKeys->hmacKey), preparedSeed, preparedSeedSize, (uint8_t *) derivedKeys, sizeof(*derivedKeys));
}