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			31 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			892 lines
		
	
	
	
		
			31 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| //-----------------------------------------------------------------------------
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| // Borrowed initially from https://github.com/nfc-tools/libfreefare
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| // Copyright (C) 2010, Romain Tartiere.
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| // Copyright (C) Proxmark3 contributors. See AUTHORS.md for details.
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| //
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| // This program is free software: you can redistribute it and/or modify
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| // it under the terms of the GNU General Public License as published by
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| // the Free Software Foundation, either version 3 of the License, or
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| // (at your option) any later version.
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| //
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| // This program is distributed in the hope that it will be useful,
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| // but WITHOUT ANY WARRANTY; without even the implied warranty of
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| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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| // GNU General Public License for more details.
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| //
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| // See LICENSE.txt for the text of the license.
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| //-----------------------------------------------------------------------------
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| /*
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|  * This implementation was written based on information provided by the
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|  * following documents:
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|  *
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|  * NIST Special Publication 800-38B
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|  * Recommendation for Block Cipher Modes of Operation: The CMAC Mode for Authentication
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|  * May 2005
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|  */
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| #include "desfire_crypto.h"
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| #include <stdlib.h>
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| #include <stdio.h>
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| #include <string.h>
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| #include "commonutil.h"
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| #include "crc32.h"
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| #include "crc.h"
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| #include "crc16.h"        // crc16 ccitt
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| #include "printf.h"
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| #include "iso14443a.h"
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| #include "dbprint.h"
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| #include "BigBuf.h"
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| 
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| #ifndef AddCrc14A
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| # define AddCrc14A(data, len) compute_crc(CRC_14443_A, (data), (len), (data)+(len), (data)+(len)+1)
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| #endif
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| 
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| static mbedtls_des_context ctx;
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| static mbedtls_des3_context ctx3;
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| static mbedtls_aes_context actx;
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| 
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| static void update_key_schedules(desfirekey_t key);
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| 
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| static void update_key_schedules(desfirekey_t key) {
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|     // DES_set_key ((DES_cblock *)key->data, &(key->ks1));
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|     // DES_set_key ((DES_cblock *)(key->data + 8), &(key->ks2));
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|     // if (T_3K3DES == key->type) {
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|     // DES_set_key ((DES_cblock *)(key->data + 16), &(key->ks3));
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|     // }
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| }
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| 
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| /******************************************************************************/
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| void des_encrypt(void *out, const void *in, const void *key) {
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|     mbedtls_des_setkey_enc(&ctx, key);
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|     mbedtls_des_crypt_ecb(&ctx, in, out);
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| }
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| 
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| void des_decrypt(void *out, const void *in, const void *key) {
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|     mbedtls_des_setkey_dec(&ctx, key);
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|     mbedtls_des_crypt_ecb(&ctx, in, out);
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| }
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| 
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| void tdes_nxp_receive(const void *in, void *out, size_t length, const void *key, unsigned char iv[8], int keymode) {
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|     if (length % 8) return;
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|     if (keymode == 2)
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|         mbedtls_des3_set2key_dec(&ctx3, key);
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|     else
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|         mbedtls_des3_set3key_dec(&ctx3, key);
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| 
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|     uint8_t i;
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|     unsigned char temp[8];
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|     uint8_t *tin = (uint8_t *) in;
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|     uint8_t *tout = (uint8_t *) out;
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| 
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|     while (length > 0) {
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|         memcpy(temp, tin, 8);
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| 
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|         mbedtls_des3_crypt_ecb(&ctx3, tin, tout);
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| 
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|         for (i = 0; i < 8; i++)
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|             tout[i] = (unsigned char)(tout[i] ^ iv[i]);
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| 
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|         memcpy(iv, temp, 8);
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| 
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|         tin  += 8;
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|         tout += 8;
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|         length -= 8;
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|     }
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| }
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| 
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| void tdes_nxp_send(const void *in, void *out, size_t length, const void *key, unsigned char iv[8], int keymode) {
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|     if (length % 8) return;
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|     if (keymode == 2)
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|         mbedtls_des3_set2key_enc(&ctx3, key);
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|     else
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|         mbedtls_des3_set3key_enc(&ctx3, key);
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| 
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|     uint8_t i;
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|     uint8_t *tin = (uint8_t *) in;
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|     uint8_t *tout = (uint8_t *) out;
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| 
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|     while (length > 0) {
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|         for (i = 0; i < 8; i++) {
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|             tin[i] = (unsigned char)(tin[i] ^ iv[i]);
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|         }
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| 
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|         mbedtls_des3_crypt_ecb(&ctx3, tin, tout);
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| 
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|         memcpy(iv, tout, 8);
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| 
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|         tin  += 8;
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|         tout += 8;
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|         length -= 8;
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|     }
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| }
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| 
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| void aes128_nxp_receive(const void *in, void *out, size_t length, const void *key, unsigned char iv[16]) {
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|     if (length % 8) return;
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| 
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|     uint8_t *tin = (uint8_t *) in;
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|     uint8_t *tout = (uint8_t *) out;
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| 
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|     mbedtls_aes_setkey_dec(&actx, key, 128);
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|     mbedtls_aes_crypt_cbc(&actx, MBEDTLS_AES_DECRYPT, length, iv, tin, tout);
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| }
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| 
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| void aes128_nxp_send(const void *in, void *out, size_t length, const void *key, unsigned char iv[16]) {
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|     if (length % 8) return;
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| 
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|     uint8_t *tin = (uint8_t *) in;
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|     uint8_t *tout = (uint8_t *) out;
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| 
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|     mbedtls_aes_setkey_enc(&actx, key, 128);
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|     mbedtls_aes_crypt_cbc(&actx, MBEDTLS_AES_ENCRYPT, length, iv, tin, tout);
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| }
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| 
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| void Desfire_des_key_new(const uint8_t value[8], desfirekey_t key) {
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|     uint8_t data[8];
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|     memcpy(data, value, 8);
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|     for (int n = 0; n < 8; n++) {
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|         data[n] &= 0xFE;
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|     }
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|     Desfire_des_key_new_with_version(data, key);
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| }
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| 
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| void Desfire_des_key_new_with_version(const uint8_t value[8], desfirekey_t key) {
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|     if (key != NULL) {
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|         key->type = T_DES;
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|         memcpy(key->data, value, 8);
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|         memcpy(key->data + 8, value, 8);
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|         update_key_schedules(key);
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|     }
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| }
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| 
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| void Desfire_3des_key_new(const uint8_t value[16], desfirekey_t key) {
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|     uint8_t data[16];
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|     memcpy(data, value, 16);
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|     for (int n = 0; n < 8; n++) {
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|         data[n] &= 0xFE;
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|     }
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|     for (int n = 8; n < 16; n++) {
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|         data[n] |= 0x01;
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|     }
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|     Desfire_3des_key_new_with_version(data, key);
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| }
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| 
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| void Desfire_3des_key_new_with_version(const uint8_t value[16], desfirekey_t key) {
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|     if (key != NULL) {
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|         key->type = T_3DES;
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|         memcpy(key->data, value, 16);
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|         update_key_schedules(key);
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|     }
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| }
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| 
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| void Desfire_3k3des_key_new(const uint8_t value[24], desfirekey_t key) {
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|     uint8_t data[24];
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|     memcpy(data, value, 24);
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|     for (int n = 0; n < 8; n++) {
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|         data[n] &= 0xFE;
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|     }
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|     Desfire_3k3des_key_new_with_version(data, key);
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| }
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| 
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| void Desfire_3k3des_key_new_with_version(const uint8_t value[24], desfirekey_t key) {
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|     if (key != NULL) {
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|         key->type = T_3K3DES;
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|         memcpy(key->data, value, 24);
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|         update_key_schedules(key);
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|     }
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| }
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| 
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| void Desfire_aes_key_new(const uint8_t value[16], desfirekey_t key) {
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|     Desfire_aes_key_new_with_version(value, 0, key);
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| }
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| 
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| void Desfire_aes_key_new_with_version(const uint8_t value[16], uint8_t version, desfirekey_t key) {
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| 
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|     if (key != NULL) {
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|         memcpy(key->data, value, 16);
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|         key->type = T_AES;
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|         key->aes_version = version;
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|     }
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| }
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| 
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| uint8_t Desfire_key_get_version(desfirekey_t key) {
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|     uint8_t version = 0;
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| 
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|     for (int n = 0; n < 8; n++) {
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|         version |= ((key->data[n] & 1) << (7 - n));
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|     }
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|     return version;
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| }
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| 
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| void Desfire_key_set_version(desfirekey_t key, uint8_t version) {
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|     for (int n = 0; n < 8; n++) {
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|         uint8_t version_bit = ((version & (1 << (7 - n))) >> (7 - n));
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|         key->data[n] &= 0xFE;
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|         key->data[n] |= version_bit;
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|         if (key->type == T_DES) {
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|             key->data[n + 8] = key->data[n];
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|         } else {
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|             // Write ~version to avoid turning a 3DES key into a DES key
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|             key->data[n + 8] &= 0xFE;
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|             key->data[n + 8] |= ~version_bit;
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|         }
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|     }
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| }
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| 
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| void Desfire_session_key_new(const uint8_t rnda[], const uint8_t rndb[], desfirekey_t authkey, desfirekey_t key) {
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| 
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|     uint8_t buffer[24];
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| 
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|     switch (authkey->type) {
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|         case T_DES:
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|             memcpy(buffer, rnda, 4);
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|             memcpy(buffer + 4, rndb, 4);
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|             Desfire_des_key_new_with_version(buffer, key);
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|             break;
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|         case T_3DES:
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|             memcpy(buffer, rnda, 4);
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|             memcpy(buffer + 4, rndb, 4);
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|             memcpy(buffer + 8, rnda + 4, 4);
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|             memcpy(buffer + 12, rndb + 4, 4);
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|             Desfire_3des_key_new_with_version(buffer, key);
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|             break;
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|         case T_3K3DES:
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|             memcpy(buffer, rnda, 4);
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|             memcpy(buffer + 4, rndb, 4);
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|             memcpy(buffer + 8, rnda + 6, 4);
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|             memcpy(buffer + 12, rndb + 6, 4);
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|             memcpy(buffer + 16, rnda + 12, 4);
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|             memcpy(buffer + 20, rndb + 12, 4);
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|             Desfire_3k3des_key_new(buffer, key);
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|             break;
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|         case T_AES:
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|             memcpy(buffer, rnda, 4);
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|             memcpy(buffer + 4, rndb, 4);
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|             memcpy(buffer + 8, rnda + 12, 4);
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|             memcpy(buffer + 12, rndb + 12, 4);
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|             Desfire_aes_key_new(buffer, key);
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|             break;
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|     }
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| }
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| 
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| static size_t key_macing_length(desfirekey_t key);
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| 
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| // iceman,  see memxor inside string.c, dest/src swapped..
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| static void xor(const uint8_t *ivect, uint8_t *data, const size_t len) {
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|     for (size_t i = 0; i < len; i++) {
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|         data[i] ^= ivect[i];
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|     }
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| }
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| 
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| void cmac_generate_subkeys(desfirekey_t key) {
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|     int kbs = key_block_size(key);
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|     const uint8_t R = (kbs == 8) ? 0x1B : 0x87;
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| 
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|     uint8_t l[kbs];
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|     memset(l, 0, kbs);
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| 
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|     uint8_t ivect[kbs];
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|     memset(ivect, 0, kbs);
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| 
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|     mifare_cypher_blocks_chained(NULL, key, ivect, l, kbs, MCD_RECEIVE, MCO_ENCYPHER);
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| 
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|     bool txor = false;
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| 
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|     // Used to compute CMAC on complete blocks
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|     memcpy(key->cmac_sk1, l, kbs);
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| 
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|     txor = l[0] & 0x80;
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| 
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|     lsl(key->cmac_sk1, kbs);
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| 
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|     if (txor) {
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|         key->cmac_sk1[kbs - 1] ^= R;
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|     }
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| 
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|     // Used to compute CMAC on the last block if non-complete
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|     memcpy(key->cmac_sk2, key->cmac_sk1, kbs);
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| 
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|     txor = key->cmac_sk1[0] & 0x80;
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| 
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|     lsl(key->cmac_sk2, kbs);
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| 
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|     if (txor) {
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|         key->cmac_sk2[kbs - 1] ^= R;
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|     }
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| }
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| 
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| void cmac(const desfirekey_t key, uint8_t *ivect, const uint8_t *data, size_t len, uint8_t *cmac) {
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|     int kbs = key_block_size(key);
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|     if (kbs == 0) {
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|         return;
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|     }
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| 
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|     uint8_t *buffer = BigBuf_malloc(padded_data_length(len, kbs));
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| 
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|     memcpy(buffer, data, len);
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| 
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|     if ((!len) || (len % kbs)) {
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|         buffer[len++] = 0x80;
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|         while (len % kbs) {
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|             buffer[len++] = 0x00;
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|         }
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|         xor(key->cmac_sk2, buffer + len - kbs, kbs);
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|     } else {
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|         xor(key->cmac_sk1, buffer + len - kbs, kbs);
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|     }
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| 
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|     mifare_cypher_blocks_chained(NULL, key, ivect, buffer, len, MCD_SEND, MCO_ENCYPHER);
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| 
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|     memcpy(cmac, ivect, kbs);
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|     //free(buffer);
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| }
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| 
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| size_t key_block_size(const desfirekey_t key) {
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|     if (key == NULL) {
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|         return 0;
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|     }
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| 
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|     size_t block_size = 8;
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|     switch (key->type) {
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|         case T_DES:
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|         case T_3DES:
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|         case T_3K3DES:
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|             block_size = 8;
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|             break;
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|         case T_AES:
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|             block_size = 16;
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|             break;
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|     }
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|     return block_size;
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| }
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| 
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| /*
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|  * Size of MACing produced with the key.
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|  */
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| static size_t key_macing_length(const desfirekey_t key) {
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|     size_t mac_length = DESFIRE_MAC_LENGTH;
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|     switch (key->type) {
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|         case T_DES:
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|         case T_3DES:
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|             mac_length = DESFIRE_MAC_LENGTH;
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|             break;
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|         case T_3K3DES:
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|         case T_AES:
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|             mac_length = DESFIRE_CMAC_LENGTH;
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|             break;
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|     }
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|     return mac_length;
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| }
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| 
 | |
| /*
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|  * Size required to store nbytes of data in a buffer of size n*block_size.
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|  */
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| size_t padded_data_length(const size_t nbytes, const size_t block_size) {
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|     if ((!nbytes) || (nbytes % block_size))
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|         return ((nbytes / block_size) + 1) * block_size;
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|     else
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|         return nbytes;
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| }
 | |
| 
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| /*
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|  * Buffer size required to MAC nbytes of data
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|  */
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| size_t maced_data_length(const desfirekey_t key, const size_t nbytes) {
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|     return nbytes + key_macing_length(key);
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| }
 | |
| /*
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|  * Buffer size required to encipher nbytes of data and a two bytes CRC.
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|  */
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| size_t enciphered_data_length(const desfiretag_t tag, const size_t nbytes, int communication_settings) {
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|     size_t crc_length = 0;
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|     if (!(communication_settings & NO_CRC)) {
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|         switch (DESFIRE(tag)->authentication_scheme) {
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|             case AS_LEGACY:
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|                 crc_length = 2;
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|                 break;
 | |
|             case AS_NEW:
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|                 crc_length = 4;
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|                 break;
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|         }
 | |
|     }
 | |
| 
 | |
|     size_t block_size = DESFIRE(tag)->session_key ? key_block_size(DESFIRE(tag)->session_key) : 1;
 | |
| 
 | |
|     return padded_data_length(nbytes + crc_length, block_size);
 | |
| }
 | |
| 
 | |
| void *mifare_cryto_preprocess_data(desfiretag_t tag, void *data, size_t *nbytes, size_t offset, int communication_settings) {
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|     uint8_t *res = data;
 | |
|     uint8_t mac[4];
 | |
|     size_t edl;
 | |
|     bool append_mac = true;
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|     desfirekey_t key = DESFIRE(tag)->session_key;
 | |
| 
 | |
|     if (!key)
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|         return data;
 | |
| 
 | |
|     switch (communication_settings & MDCM_MASK) {
 | |
|         case MDCM_PLAIN:
 | |
|             if (AS_LEGACY == DESFIRE(tag)->authentication_scheme)
 | |
|                 break;
 | |
| 
 | |
|             /*
 | |
|              * When using new authentication methods, PLAIN data transmission from
 | |
|              * the PICC to the PCD are CMACed, so we have to maintain the
 | |
|              * cryptographic initialisation vector up-to-date to check data
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|              * integrity later.
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|              *
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|              * The only difference with CMACed data transmission is that the CMAC
 | |
|              * is not appended to the data send by the PCD to the PICC.
 | |
|              */
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| 
 | |
|             append_mac = false;
 | |
| 
 | |
|         /* pass through */
 | |
|         case MDCM_MACED:
 | |
|             switch (DESFIRE(tag)->authentication_scheme) {
 | |
|                 case AS_LEGACY:
 | |
|                     if (!(communication_settings & MAC_COMMAND))
 | |
|                         break;
 | |
| 
 | |
|                     /* pass through */
 | |
|                     edl = padded_data_length(*nbytes - offset, key_block_size(DESFIRE(tag)->session_key)) + offset;
 | |
| 
 | |
|                     // Fill in the crypto buffer with data ...
 | |
|                     memcpy(res, data, *nbytes);
 | |
|                     // ... and 0 padding
 | |
|                     memset(res + *nbytes, 0, edl - *nbytes);
 | |
| 
 | |
|                     mifare_cypher_blocks_chained(tag, NULL, NULL, res + offset, edl - offset, MCD_SEND, MCO_ENCYPHER);
 | |
| 
 | |
|                     memcpy(mac, res + edl - 8, 4);
 | |
| 
 | |
|                     // Copy again provided data (was overwritten by mifare_cypher_blocks_chained)
 | |
|                     memcpy(res, data, *nbytes);
 | |
| 
 | |
|                     if (!(communication_settings & MAC_COMMAND))
 | |
|                         break;
 | |
|                     // Append MAC
 | |
|                     size_t bla = maced_data_length(DESFIRE(tag)->session_key, *nbytes - offset) + offset;
 | |
|                     (void)bla++;
 | |
| 
 | |
|                     memcpy(res + *nbytes, mac, 4);
 | |
| 
 | |
|                     *nbytes += 4;
 | |
|                     break;
 | |
|                 case AS_NEW:
 | |
|                     if (!(communication_settings & CMAC_COMMAND))
 | |
|                         break;
 | |
|                     cmac(key, DESFIRE(tag)->ivect, res, *nbytes, DESFIRE(tag)->cmac);
 | |
| 
 | |
|                     if (append_mac) {
 | |
|                         size_t len = maced_data_length(key, *nbytes);
 | |
|                         (void)++len;
 | |
|                         memcpy(res, data, *nbytes);
 | |
|                         memcpy(res + *nbytes, DESFIRE(tag)->cmac, DESFIRE_CMAC_LENGTH);
 | |
|                         *nbytes += DESFIRE_CMAC_LENGTH;
 | |
|                     }
 | |
|                     break;
 | |
|             }
 | |
| 
 | |
|             break;
 | |
|         case MDCM_ENCIPHERED:
 | |
|             /*  |<-------------- data -------------->|
 | |
|              *  |<--- offset -->|                    |
 | |
|              *  +---------------+--------------------+-----+---------+
 | |
|              *  | CMD + HEADERS | DATA TO BE SECURED | CRC | PADDING |
 | |
|              *  +---------------+--------------------+-----+---------+ ----------------
 | |
|              *  |               |<~~~~v~~~~~~~~~~~~~>|  ^  |         |   (DES / 3DES)
 | |
|              *  |               |     `---- crc16() ----'  |         |
 | |
|              *  |               |                    |  ^  |         | ----- *or* -----
 | |
|              *  |<~~~~~~~~~~~~~~~~~~~~v~~~~~~~~~~~~~>|  ^  |         |  (3K3DES / AES)
 | |
|              *                  |     `---- crc32() ----'  |         |
 | |
|              *                  |                                    | ---- *then* ----
 | |
|              *                  |<---------------------------------->|
 | |
|              *                            encypher()/decypher()
 | |
|              */
 | |
| 
 | |
|             if (!(communication_settings & ENC_COMMAND))
 | |
|                 break;
 | |
|             edl = enciphered_data_length(tag, *nbytes - offset, communication_settings) + offset;
 | |
| 
 | |
|             // Fill in the crypto buffer with data ...
 | |
|             memcpy(res, data, *nbytes);
 | |
|             if (!(communication_settings & NO_CRC)) {
 | |
|                 // ... CRC ...
 | |
|                 switch (DESFIRE(tag)->authentication_scheme) {
 | |
|                     case AS_LEGACY:
 | |
|                         AddCrc14A(res + offset, *nbytes - offset);
 | |
|                         *nbytes += 2;
 | |
|                         break;
 | |
|                     case AS_NEW:
 | |
|                         crc32_append(res, *nbytes);
 | |
|                         *nbytes += 4;
 | |
|                         break;
 | |
|                 }
 | |
|             }
 | |
|             // ... and padding
 | |
|             memset(res + *nbytes, 0, edl - *nbytes);
 | |
| 
 | |
|             *nbytes = edl;
 | |
| 
 | |
|             mifare_cypher_blocks_chained(tag, NULL, NULL, res + offset, *nbytes - offset, MCD_SEND, (AS_NEW == DESFIRE(tag)->authentication_scheme) ? MCO_ENCYPHER : MCO_DECYPHER);
 | |
|             break;
 | |
|         default:
 | |
| 
 | |
|             *nbytes = -1;
 | |
|             res = NULL;
 | |
|             break;
 | |
|     }
 | |
| 
 | |
|     return res;
 | |
| 
 | |
| }
 | |
| 
 | |
| void *mifare_cryto_postprocess_data(desfiretag_t tag, void *data, size_t *nbytes, int communication_settings) {
 | |
|     void *res = data;
 | |
|     void *edata = NULL;
 | |
|     uint8_t first_cmac_byte = 0x00;
 | |
| 
 | |
|     desfirekey_t key = DESFIRE(tag)->session_key;
 | |
| 
 | |
|     if (!key)
 | |
|         return data;
 | |
| 
 | |
|     // Return directly if we just have a status code.
 | |
|     if (1 == *nbytes)
 | |
|         return res;
 | |
| 
 | |
|     switch (communication_settings & MDCM_MASK) {
 | |
|         case MDCM_PLAIN:
 | |
| 
 | |
|             if (AS_LEGACY == DESFIRE(tag)->authentication_scheme)
 | |
|                 break;
 | |
| 
 | |
|         /* pass through */
 | |
|         case MDCM_MACED:
 | |
|             switch (DESFIRE(tag)->authentication_scheme) {
 | |
|                 case AS_LEGACY:
 | |
|                     if (communication_settings & MAC_VERIFY) {
 | |
|                         *nbytes -= key_macing_length(key);
 | |
|                         if (*nbytes == 0) {
 | |
|                             *nbytes = -1;
 | |
|                             res = NULL;
 | |
| #ifdef WITH_DEBUG
 | |
|                             Dbprintf("No room for MAC!");
 | |
| #endif
 | |
|                             break;
 | |
|                         }
 | |
| 
 | |
|                         size_t edl = enciphered_data_length(tag, *nbytes - 1, communication_settings);
 | |
|                         edata = BigBuf_malloc(edl);
 | |
| 
 | |
|                         memcpy(edata, data, *nbytes - 1);
 | |
|                         memset((uint8_t *)edata + *nbytes - 1, 0, edl - *nbytes + 1);
 | |
| 
 | |
|                         mifare_cypher_blocks_chained(tag, NULL, NULL, edata, edl, MCD_SEND, MCO_ENCYPHER);
 | |
| 
 | |
|                         if (0 != memcmp((uint8_t *)data + *nbytes - 1, (uint8_t *)edata + edl - 8, 4)) {
 | |
| #ifdef WITH_DEBUG
 | |
|                             Dbprintf("MACing not verified");
 | |
|                             hexdump((uint8_t *)data + *nbytes - 1, key_macing_length(key), "Expect ", 0);
 | |
|                             hexdump((uint8_t *)edata + edl - 8, key_macing_length(key), "Actual ", 0);
 | |
| #endif
 | |
|                             DESFIRE(tag)->last_pcd_error = CRYPTO_ERROR;
 | |
|                             *nbytes = -1;
 | |
|                             res = NULL;
 | |
|                         }
 | |
|                     }
 | |
|                     break;
 | |
|                 case AS_NEW:
 | |
|                     if (!(communication_settings & CMAC_COMMAND))
 | |
|                         break;
 | |
|                     if (communication_settings & CMAC_VERIFY) {
 | |
|                         if (*nbytes < 9) {
 | |
|                             *nbytes = -1;
 | |
|                             res = NULL;
 | |
|                             break;
 | |
|                         }
 | |
|                         first_cmac_byte = ((uint8_t *)data)[*nbytes - 9];
 | |
|                         ((uint8_t *)data)[*nbytes - 9] = ((uint8_t *)data)[*nbytes - 1];
 | |
|                     }
 | |
| 
 | |
|                     int n = (communication_settings & CMAC_VERIFY) ? 8 : 0;
 | |
|                     cmac(key, DESFIRE(tag)->ivect, ((uint8_t *)data), *nbytes - n, DESFIRE(tag)->cmac);
 | |
| 
 | |
|                     if (communication_settings & CMAC_VERIFY) {
 | |
|                         ((uint8_t *)data)[*nbytes - 9] = first_cmac_byte;
 | |
|                         if (0 != memcmp(DESFIRE(tag)->cmac, (uint8_t *)data + *nbytes - 9, 8)) {
 | |
| #ifdef WITH_DEBUG
 | |
|                             Dbprintf("CMAC NOT verified :-(");
 | |
|                             hexdump((uint8_t *)data + *nbytes - 9, 8, "Expect ", 0);
 | |
|                             hexdump(DESFIRE(tag)->cmac, 8, "Actual ", 0);
 | |
| #endif
 | |
|                             DESFIRE(tag)->last_pcd_error = CRYPTO_ERROR;
 | |
|                             *nbytes = -1;
 | |
|                             res = NULL;
 | |
|                         } else {
 | |
|                             *nbytes -= 8;
 | |
|                         }
 | |
|                     }
 | |
|                     break;
 | |
|             }
 | |
| 
 | |
|             free(edata);
 | |
| 
 | |
|             break;
 | |
|         case MDCM_ENCIPHERED:
 | |
|             (*nbytes)--;
 | |
|             bool verified = false;
 | |
|             int crc_pos = 0x00;
 | |
|             int end_crc_pos = 0x00;
 | |
|             uint8_t x;
 | |
| 
 | |
|             /*
 | |
|              * AS_LEGACY:
 | |
|              * ,-----------------+-------------------------------+--------+
 | |
|              * \     BLOCK n-1   |              BLOCK n          | STATUS |
 | |
|              * /  PAYLOAD | CRC0 | CRC1 | 0x80? | 0x000000000000 | 0x9100 |
 | |
|              * `-----------------+-------------------------------+--------+
 | |
|              *
 | |
|              *         <------------ DATA ------------>
 | |
|              * FRAME = PAYLOAD + CRC(PAYLOAD) + PADDING
 | |
|              *
 | |
|              * AS_NEW:
 | |
|              * ,-------------------------------+-----------------------------------------------+--------+
 | |
|              * \                 BLOCK n-1     |                  BLOCK n                      | STATUS |
 | |
|              * /  PAYLOAD | CRC0 | CRC1 | CRC2 | CRC3 | 0x80? | 0x0000000000000000000000000000 | 0x9100 |
 | |
|              * `-------------------------------+-----------------------------------------------+--------+
 | |
|              * <----------------------------------- DATA ------------------------------------->|
 | |
|              *
 | |
|              *         <----------------- DATA ---------------->
 | |
|              * FRAME = PAYLOAD + CRC(PAYLOAD + STATUS) + PADDING + STATUS
 | |
|              *                                    `------------------'
 | |
|              */
 | |
| 
 | |
|             mifare_cypher_blocks_chained(tag, NULL, NULL, res, *nbytes, MCD_RECEIVE, MCO_DECYPHER);
 | |
| 
 | |
|             /*
 | |
|              * Look for the CRC and ensure it is followed by NULL padding.  We
 | |
|              * can't start by the end because the CRC is supposed to be 0 when
 | |
|              * verified, and accumulating 0's in it should not change it.
 | |
|              */
 | |
|             switch (DESFIRE(tag)->authentication_scheme) {
 | |
|                 case AS_LEGACY:
 | |
|                     crc_pos = *nbytes - 8 - 1; // The CRC can be over two blocks
 | |
|                     if (crc_pos < 0) {
 | |
|                         /* Single block */
 | |
|                         crc_pos = 0;
 | |
|                     }
 | |
|                     break;
 | |
|                 case AS_NEW:
 | |
|                     /* Move status between payload and CRC */
 | |
|                     res = DESFIRE(tag)->crypto_buffer;
 | |
|                     memcpy(res, data, *nbytes);
 | |
| 
 | |
|                     crc_pos = (*nbytes) - 16 - 3;
 | |
|                     if (crc_pos < 0) {
 | |
|                         /* Single block */
 | |
|                         crc_pos = 0;
 | |
|                     }
 | |
|                     memcpy((uint8_t *)res + crc_pos + 1, (uint8_t *)res + crc_pos, *nbytes - crc_pos);
 | |
|                     ((uint8_t *)res)[crc_pos] = 0x00;
 | |
|                     crc_pos++;
 | |
|                     *nbytes += 1;
 | |
|                     break;
 | |
|             }
 | |
| 
 | |
|             do {
 | |
|                 uint16_t crc_16 = 0x00;
 | |
|                 uint32_t crc = 0x00;
 | |
|                 switch (DESFIRE(tag)->authentication_scheme) {
 | |
|                     case AS_LEGACY:
 | |
|                         AddCrc14A((uint8_t *)res, end_crc_pos);
 | |
|                         end_crc_pos = crc_pos + 2;
 | |
|                         //
 | |
| 
 | |
| 
 | |
|                         crc = crc_16;
 | |
|                         break;
 | |
|                     case AS_NEW:
 | |
|                         end_crc_pos = crc_pos + 4;
 | |
|                         crc32_ex(res, end_crc_pos, (uint8_t *)&crc);
 | |
|                         break;
 | |
|                 }
 | |
|                 if (!crc) {
 | |
|                     verified = true;
 | |
|                     for (int n = end_crc_pos; n < *nbytes - 1; n++) {
 | |
|                         uint8_t byte = ((uint8_t *)res)[n];
 | |
|                         if (!((0x00 == byte) || ((0x80 == byte) && (n == end_crc_pos))))
 | |
|                             verified = false;
 | |
|                     }
 | |
|                 }
 | |
|                 if (verified) {
 | |
|                     *nbytes = crc_pos;
 | |
|                     switch (DESFIRE(tag)->authentication_scheme) {
 | |
|                         case AS_LEGACY:
 | |
|                             ((uint8_t *)data)[(*nbytes)++] = 0x00;
 | |
|                             break;
 | |
|                         case AS_NEW:
 | |
|                             /* The status byte was already before the CRC */
 | |
|                             break;
 | |
|                     }
 | |
|                 } else {
 | |
|                     switch (DESFIRE(tag)->authentication_scheme) {
 | |
|                         case AS_LEGACY:
 | |
|                             break;
 | |
|                         case AS_NEW:
 | |
|                             x = ((uint8_t *)res)[crc_pos - 1];
 | |
|                             ((uint8_t *)res)[crc_pos - 1] = ((uint8_t *)res)[crc_pos];
 | |
|                             ((uint8_t *)res)[crc_pos] = x;
 | |
|                             break;
 | |
|                     }
 | |
|                     crc_pos++;
 | |
|                 }
 | |
|             } while (!verified && (end_crc_pos < *nbytes));
 | |
| 
 | |
|             if (!verified) {
 | |
| #ifdef WITH_DEBUG
 | |
|                 /* FIXME In some configurations, the file is transmitted PLAIN */
 | |
|                 Dbprintf("CRC not verified in decyphered stream");
 | |
| #endif
 | |
|                 DESFIRE(tag)->last_pcd_error = CRYPTO_ERROR;
 | |
|                 *nbytes = -1;
 | |
|                 res = NULL;
 | |
|             }
 | |
| 
 | |
|             break;
 | |
|         default:
 | |
|             Dbprintf("Unknown communication settings");
 | |
|             *nbytes = -1;
 | |
|             res = NULL;
 | |
|             break;
 | |
| 
 | |
|     }
 | |
|     return res;
 | |
| }
 | |
| 
 | |
| 
 | |
| void mifare_cypher_single_block(desfirekey_t key, uint8_t *data, uint8_t *ivect, MifareCryptoDirection direction, MifareCryptoOperation operation, size_t block_size) {
 | |
|     uint8_t ovect[DESFIRE_MAX_CRYPTO_BLOCK_SIZE];
 | |
|     if (direction == MCD_SEND) {
 | |
|         xor(ivect, data, block_size);
 | |
|     } else {
 | |
|         memcpy(ovect, data, block_size);
 | |
|     }
 | |
| 
 | |
|     uint8_t edata[DESFIRE_MAX_CRYPTO_BLOCK_SIZE] = {0};
 | |
| 
 | |
|     switch (key->type) {
 | |
|         case T_DES:
 | |
|             switch (operation) {
 | |
|                 case MCO_ENCYPHER:
 | |
|                     //DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_ENCRYPT);
 | |
|                     des_encrypt(edata, data, key->data);
 | |
|                     break;
 | |
|                 case MCO_DECYPHER:
 | |
|                     //DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_DECRYPT);
 | |
|                     des_decrypt(edata, data, key->data);
 | |
|                     break;
 | |
|             }
 | |
|             break;
 | |
|         case T_3DES:
 | |
|             switch (operation) {
 | |
|                 case MCO_ENCYPHER:
 | |
|                     mbedtls_des3_set2key_enc(&ctx3, key->data);
 | |
|                     mbedtls_des3_crypt_ecb(&ctx3, data, edata);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) data,  (DES_cblock *) edata, &(key->ks1), DES_ENCRYPT);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) edata, (DES_cblock *) data,  &(key->ks2), DES_DECRYPT);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) data,  (DES_cblock *) edata, &(key->ks1), DES_ENCRYPT);
 | |
|                     break;
 | |
|                 case MCO_DECYPHER:
 | |
|                     mbedtls_des3_set2key_dec(&ctx3, key->data);
 | |
|                     mbedtls_des3_crypt_ecb(&ctx3, data, edata);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) data,  (DES_cblock *) edata, &(key->ks1), DES_DECRYPT);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) edata, (DES_cblock *) data,  &(key->ks2), DES_ENCRYPT);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) data,  (DES_cblock *) edata, &(key->ks1), DES_DECRYPT);
 | |
|                     break;
 | |
|             }
 | |
|             break;
 | |
|         case T_3K3DES:
 | |
|             switch (operation) {
 | |
|                 case MCO_ENCYPHER:
 | |
|                     mbedtls_des3_set3key_enc(&ctx3, key->data);
 | |
|                     mbedtls_des3_crypt_ecb(&ctx3, data, edata);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) data,  (DES_cblock *) edata, &(key->ks1), DES_ENCRYPT);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) edata, (DES_cblock *) data,  &(key->ks2), DES_DECRYPT);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) data,  (DES_cblock *) edata, &(key->ks3), DES_ENCRYPT);
 | |
|                     break;
 | |
|                 case MCO_DECYPHER:
 | |
|                     mbedtls_des3_set3key_dec(&ctx3, key->data);
 | |
|                     mbedtls_des3_crypt_ecb(&ctx3, data, edata);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) data,  (DES_cblock *) edata, &(key->ks3), DES_DECRYPT);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) edata, (DES_cblock *) data,  &(key->ks2), DES_ENCRYPT);
 | |
|                     // DES_ecb_encrypt ((DES_cblock *) data,  (DES_cblock *) edata, &(key->ks1), DES_DECRYPT);
 | |
|                     break;
 | |
|             }
 | |
|             break;
 | |
|         case T_AES:
 | |
|             switch (operation) {
 | |
|                 case MCO_ENCYPHER: {
 | |
|                     mbedtls_aes_init(&actx);
 | |
|                     mbedtls_aes_setkey_enc(&actx, key->data, 128);
 | |
|                     mbedtls_aes_crypt_cbc(&actx, MBEDTLS_AES_ENCRYPT, sizeof(edata), ivect, data, edata);
 | |
|                     break;
 | |
|                 }
 | |
|                 case MCO_DECYPHER: {
 | |
|                     mbedtls_aes_init(&actx);
 | |
|                     mbedtls_aes_setkey_dec(&actx, key->data, 128);
 | |
|                     mbedtls_aes_crypt_cbc(&actx, MBEDTLS_AES_DECRYPT, sizeof(edata), ivect, edata, data);
 | |
|                     break;
 | |
|                 }
 | |
|             }
 | |
|             break;
 | |
|     }
 | |
| 
 | |
|     memcpy(data, edata, block_size);
 | |
| 
 | |
|     if (direction == MCD_SEND) {
 | |
|         memcpy(ivect, data, block_size);
 | |
|     } else {
 | |
|         xor(ivect, data, block_size);
 | |
|         memcpy(ivect, ovect, block_size);
 | |
|     }
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * This function performs all CBC cyphering / deciphering.
 | |
|  *
 | |
|  * The tag argument may be NULL, in which case both key and ivect shall be set.
 | |
|  * When using the tag session_key and ivect for processing data, these
 | |
|  * arguments should be set to NULL.
 | |
|  *
 | |
|  * Because the tag may contain additional data, one may need to call this
 | |
|  * function with tag, key and ivect defined.
 | |
|  */
 | |
| void mifare_cypher_blocks_chained(desfiretag_t tag, desfirekey_t key, uint8_t *ivect, uint8_t *data, size_t data_size, MifareCryptoDirection direction, MifareCryptoOperation operation) {
 | |
|     size_t block_size;
 | |
| 
 | |
|     if (tag) {
 | |
|         if (key == NULL) {
 | |
|             key = DESFIRE(tag)->session_key;
 | |
|         }
 | |
|         if (ivect == NULL) {
 | |
|             ivect = DESFIRE(tag)->ivect;
 | |
|         }
 | |
| 
 | |
|         switch (DESFIRE(tag)->authentication_scheme) {
 | |
|             case AS_LEGACY:
 | |
|                 memset(ivect, 0, DESFIRE_MAX_CRYPTO_BLOCK_SIZE);
 | |
|                 break;
 | |
|             case AS_NEW:
 | |
|                 break;
 | |
|         }
 | |
|     }
 | |
| 
 | |
|     block_size = key_block_size(key);
 | |
| 
 | |
|     size_t offset = 0;
 | |
|     while (offset < data_size) {
 | |
|         mifare_cypher_single_block(key, data + offset, ivect, direction, operation, block_size);
 | |
|         offset += block_size;
 | |
|     }
 | |
| }
 |