int CmdG_Prox_II_Demod(const char *Cmd)
{
if (!ASKbiphaseDemod(Cmd, FALSE)){
- if (g_debugMode) PrintAndLog("ASKbiphaseDemod failed 1st try");
+ if (g_debugMode) PrintAndLog("Error gProxII: ASKbiphaseDemod failed 1st try");
return 0;
}
size_t size = DemodBufferLen;
if (g_debugMode) PrintAndLog("Error gProxII_Demod");
return 0;
}
- //got a good demod
- uint32_t ByteStream[65] = {0x00};
+ //got a good demod of 96 bits
+ uint8_t ByteStream[8] = {0x00};
uint8_t xorKey=0;
- uint8_t keyCnt=0;
- uint8_t bitCnt=0;
- uint8_t ByteCnt=0;
- size_t startIdx = ans + 6; //start after preamble
- for (size_t idx = 0; idx<size-6; idx++){
- if ((idx+1) % 5 == 0){
- //spacer bit - should be 0
- if (DemodBuffer[startIdx+idx] != 0) {
- if (g_debugMode) PrintAndLog("Error spacer not 0: %u, pos: %u", (unsigned int)DemodBuffer[startIdx+idx],(unsigned int)(startIdx+idx));
+ size_t startIdx = ans + 6; //start after 6 bit preamble
+
+ uint8_t bits_no_spacer[90];
+ //so as to not mess with raw DemodBuffer copy to a new sample array
+ memcpy(bits_no_spacer, DemodBuffer + startIdx, 90);
+ // remove the 18 (90/5=18) parity bits (down to 72 bits (96-6-18=72))
+ size_t bitLen = removeParity(bits_no_spacer, 0, 5, 3, 90); //source, startloc, paritylen, ptype, length_to_run
+ if (bitLen != 72) {
+ if (g_debugMode) PrintAndLog("Error gProxII: spacer removal did not produce 72 bits: %u, start: %u", bitLen, startIdx);
return 0;
}
- continue;
- }
- if (keyCnt<8){ //lsb first
- xorKey = xorKey | (DemodBuffer[startIdx+idx]<<keyCnt);
- keyCnt++;
- if (keyCnt==8 && g_debugMode) PrintAndLog("xorKey Found: %02x", xorKey);
- continue;
- }
- //lsb first
- ByteStream[ByteCnt] = ByteStream[ByteCnt] | (DemodBuffer[startIdx+idx]<<bitCnt);
- bitCnt++;
- if (bitCnt % 8 == 0){
- if (g_debugMode) PrintAndLog("byte %u: %02x", (unsigned int)ByteCnt, ByteStream[ByteCnt]);
- bitCnt=0;
- ByteCnt++;
- }
- }
- for (uint8_t i = 0; i < ByteCnt; i++){
- ByteStream[i] ^= xorKey; //xor
- if (g_debugMode) PrintAndLog("byte %u after xor: %02x", (unsigned int)i, ByteStream[i]);
+ // get key and then get all 8 bytes of payload decoded
+ xorKey = (uint8_t)bytebits_to_byteLSBF(bits_no_spacer, 8);
+ for (size_t idx = 0; idx < 8; idx++) {
+ ByteStream[idx] = ((uint8_t)bytebits_to_byteLSBF(bits_no_spacer+8 + (idx*8),8)) ^ xorKey;
+ if (g_debugMode) PrintAndLog("byte %u after xor: %02x", (unsigned int)idx, ByteStream[idx]);
}
- //now ByteStream contains 64 bytes of decrypted raw tag data
+ //now ByteStream contains 8 Bytes (64 bits) of decrypted raw tag data
//
uint8_t fmtLen = ByteStream[0]>>2;
uint32_t FC = 0;
uint32_t Card = 0;
+ //get raw 96 bits to print
uint32_t raw1 = bytebits_to_byte(DemodBuffer+ans,32);
uint32_t raw2 = bytebits_to_byte(DemodBuffer+ans+32, 32);
uint32_t raw3 = bytebits_to_byte(DemodBuffer+ans+64, 32);
if (fmtLen==36){
FC = ((ByteStream[3] & 0x7F)<<7) | (ByteStream[4]>>1);
Card = ((ByteStream[4]&1)<<19) | (ByteStream[5]<<11) | (ByteStream[6]<<3) | (ByteStream[7]>>5);
- PrintAndLog("G-Prox-II Found: FmtLen %d, FC %d, Card %d",fmtLen,FC,Card);
+ PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
} else if(fmtLen==26){
FC = ((ByteStream[3] & 0x7F)<<1) | (ByteStream[4]>>7);
Card = ((ByteStream[4]&0x7F)<<9) | (ByteStream[5]<<1) | (ByteStream[6]>>7);
- PrintAndLog("G-Prox-II Found: FmtLen %d, FC %d, Card %d",fmtLen,FC,Card);
+ PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
} else {
- PrintAndLog("Unknown G-Prox-II Fmt Found: FmtLen %d",fmtLen);
+ PrintAndLog("Unknown G-Prox-II Fmt Found: FmtLen %d",(int)fmtLen);
+ PrintAndLog("Decoded Raw: %s", sprint_hex(ByteStream, 8));
}
PrintAndLog("Raw: %08x%08x%08x", raw1,raw2,raw3);
setDemodBuf(DemodBuffer+ans, 96, 0);