+ // authenticate\r
+ if ( useKey ) {\r
+ \r
+ uint8_t key[16] = {0x00}; \r
+ memcpy(key, datain, 16);\r
+ \r
+ uint8_t random_a[8] = {1,1,1,1,1,1,1,1 };\r
+ uint8_t random_b[8] = {0x00};\r
+ uint8_t enc_random_b[8] = {0x00};\r
+ uint8_t rnd_ab[16] = {0x00};\r
+ uint8_t IV[8] = {0x00};\r
+ \r
+ uint16_t len;\r
+ uint8_t receivedAnswer[MAX_FRAME_SIZE];\r
+ uint8_t receivedAnswerPar[MAX_PARITY_SIZE];\r
+ \r
+ len = mifare_sendcmd_short(NULL, 1, 0x1A, 0x00, receivedAnswer,receivedAnswerPar ,NULL);\r
+ if (len != 11) {\r
+ if (MF_DBGLEVEL >= MF_DBG_ERROR) Dbprintf("Cmd Error: %02x", receivedAnswer[0]);\r
+ OnError(1);\r
+ return;\r
+ }\r
+ \r
+ // tag nonce.\r
+ memcpy(enc_random_b,receivedAnswer+1,8);\r
+\r
+ // decrypt nonce.\r
+ tdes_2key_dec(random_b, enc_random_b, sizeof(random_b), key, IV );\r
+ rol(random_b,8);\r
+ memcpy(rnd_ab ,random_a,8);\r
+ memcpy(rnd_ab+8,random_b,8);\r
+ \r
+ // encrypt out, in, length, key, iv\r
+ tdes_2key_enc(rnd_ab, rnd_ab, sizeof(rnd_ab), key, enc_random_b);\r
+\r
+ len = mifare_sendcmd_short_mfucauth(NULL, 1, 0xAF, rnd_ab, receivedAnswer, receivedAnswerPar, NULL);\r
+ if (len != 11) {\r
+ OnError(1);\r
+ return;\r
+ }\r
+\r
+ uint8_t enc_resp[8] = { 0 };\r
+ uint8_t resp_random_a[8] = { 0 };\r
+ memcpy(enc_resp, receivedAnswer+1, 8);\r
+ \r
+ // decrypt out, in, length, key, iv \r
+ tdes_2key_dec(resp_random_a, enc_resp, 8, key, enc_random_b);\r
+ if ( memcmp(resp_random_a, random_a, 8) != 0 )\r
+ Dbprintf("failed authentication");\r
+ }\r
+ \r
+ for (int i = 0; i < blocks; i++){\r