mirror of
https://github.com/RfidResearchGroup/proxmark3.git
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54 lines
1.8 KiB
C
54 lines
1.8 KiB
C
/*
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* (c) 2015-2017 Marcos Del Sol Vives
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*
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* SPDX-License-Identifier: MIT
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*/
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#include "drbg.h"
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#include "keygen.h"
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#include <assert.h>
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#include <stdio.h>
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#include <string.h>
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static void nfc3d_keygen_prepare_seed(const nfc3d_keygen_masterkeys_t *baseKeys, const uint8_t *baseSeed, uint8_t *output, size_t *outputSize) {
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assert(baseKeys != NULL);
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assert(baseSeed != NULL);
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assert(output != NULL);
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assert(outputSize != NULL);
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uint8_t *start = output;
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// 1: Copy whole type string
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// output = (uint8_t *)strcpy((char *)output, baseKeys->typeString);
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output = memccpy(output, baseKeys->typeString, '\0', sizeof(baseKeys->typeString));
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// 2: Append (16 - magicBytesSize) from the input seed
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size_t leadingSeedBytes = 16 - baseKeys->magicBytesSize;
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memcpy(output, baseSeed, leadingSeedBytes);
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output += leadingSeedBytes;
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// 3: Append all bytes from magicBytes
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memcpy(output, baseKeys->magicBytes, baseKeys->magicBytesSize);
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output += baseKeys->magicBytesSize;
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// 4: Append bytes 0x10-0x1F from input seed
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memcpy(output, baseSeed + 0x10, 16);
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output += 16;
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// 5: Xor last bytes 0x20-0x3F of input seed with AES XOR pad and append them
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unsigned int i;
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for (i = 0; i < 32; i++) {
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output[i] = baseSeed[i + 32] ^ baseKeys->xorPad[i];
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}
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output += 32;
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*outputSize = output - start;
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}
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void nfc3d_keygen(const nfc3d_keygen_masterkeys_t *baseKeys, const uint8_t *baseSeed, nfc3d_keygen_derivedkeys_t *derivedKeys) {
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uint8_t preparedSeed[NFC3D_DRBG_MAX_SEED_SIZE];
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size_t preparedSeedSize;
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nfc3d_keygen_prepare_seed(baseKeys, baseSeed, preparedSeed, &preparedSeedSize);
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nfc3d_drbg_generate_bytes(baseKeys->hmacKey, sizeof(baseKeys->hmacKey), preparedSeed, preparedSeedSize, (uint8_t *) derivedKeys, sizeof(*derivedKeys));
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}
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