From 84c02e97e0925a44daece47ce19c265e22d5c772 Mon Sep 17 00:00:00 2001 From: "roel@libnfc.org" Date: Mon, 28 Dec 2009 17:21:50 +0000 Subject: [PATCH] iso14443a cleanup, cascade2 level working again --- armsrc/iso14443a.c | 548 ++++++++++++++++++++------------------------- 1 file changed, 242 insertions(+), 306 deletions(-) diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c index a02d7d42..d39fbdd4 100644 --- a/armsrc/iso14443a.c +++ b/armsrc/iso14443a.c @@ -39,6 +39,13 @@ static const BYTE OddByteParity[256] = { 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1 }; +// BIG CHANGE - UNDERSTAND THIS BEFORE WE COMMIT +#define RECV_CMD_OFFSET 3032 +#define RECV_RES_OFFSET 3096 +#define DMA_BUFFER_OFFSET 3160 +#define DMA_BUFFER_SIZE 4096 +#define TRACE_LENGTH 3000 + //----------------------------------------------------------------------------- // Generate the parity value for a byte sequence // @@ -56,6 +63,35 @@ DWORD GetParity(const BYTE * pbtCmd, int iLen) return dwPar; } +static void AppendCrc14443a(BYTE* data, int len) +{ + ComputeCrc14443(CRC_14443_A,data,len,data+len,data+len+1); +} + +BOOL LogTrace(const BYTE * btBytes, int iLen, int iSamples, DWORD dwParity, BOOL bReader) +{ + // Return when trace is full + if (traceLen >= TRACE_LENGTH) return FALSE; + + // Trace the random, i'm curious + rsamples += iSamples; + trace[traceLen++] = ((rsamples >> 0) & 0xff); + trace[traceLen++] = ((rsamples >> 8) & 0xff); + trace[traceLen++] = ((rsamples >> 16) & 0xff); + trace[traceLen++] = ((rsamples >> 24) & 0xff); + if (!bReader) { + trace[traceLen - 1] |= 0x80; + } + trace[traceLen++] = ((dwParity >> 0) & 0xff); + trace[traceLen++] = ((dwParity >> 8) & 0xff); + trace[traceLen++] = ((dwParity >> 16) & 0xff); + trace[traceLen++] = ((dwParity >> 24) & 0xff); + trace[traceLen++] = iLen; + memcpy(trace + traceLen, btBytes, iLen); + traceLen += iLen; + return TRUE; +} + //----------------------------------------------------------------------------- // The software UART that receives commands from the reader, and its state // variables. @@ -549,15 +585,6 @@ static BOOL ManchesterDecoding(int v) //----------------------------------------------------------------------------- void SnoopIso14443a(void) { - - // BIG CHANGE - UNDERSTAND THIS BEFORE WE COMMIT - - #define RECV_CMD_OFFSET 3032 - #define RECV_RES_OFFSET 3096 - #define DMA_BUFFER_OFFSET 3160 - #define DMA_BUFFER_SIZE 4096 - #define TRACE_LENGTH 3000 - // #define RECV_CMD_OFFSET 2032 // original (working as of 21/2/09) values // #define RECV_RES_OFFSET 2096 // original (working as of 21/2/09) values // #define DMA_BUFFER_OFFSET 2160 // original (working as of 21/2/09) values @@ -874,27 +901,6 @@ static void CodeStrangeAnswer() //ToSendMax += 2; } -int LogTrace(const BYTE * btBytes, int iLen, int iSamples, DWORD dwParity, BOOL bReader) -{ - // Trace the random, i'm curious - rsamples += iSamples; - trace[traceLen++] = ((rsamples >> 0) & 0xff); - trace[traceLen++] = ((rsamples >> 8) & 0xff); - trace[traceLen++] = ((rsamples >> 16) & 0xff); - trace[traceLen++] = ((rsamples >> 24) & 0xff); - if (!bReader) { - trace[traceLen - 1] |= 0x80; - } - trace[traceLen++] = ((dwParity >> 0) & 0xff); - trace[traceLen++] = ((dwParity >> 8) & 0xff); - trace[traceLen++] = ((dwParity >> 16) & 0xff); - trace[traceLen++] = ((dwParity >> 24) & 0xff); - trace[traceLen++] = iLen; - memcpy(trace + traceLen, btBytes, iLen); - traceLen += iLen; - return (traceLen < TRACE_LENGTH); -} - //----------------------------------------------------------------------------- // Wait for commands from reader // Stop when button is pressed @@ -1231,40 +1237,42 @@ ComputeCrc14443(CRC_14443_A, response3a, 1, &response3a[1], &response3a[2]); //----------------------------------------------------------------------------- static void TransmitFor14443a(const BYTE *cmd, int len, int *samples, int *wait) { - int c; - - FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); - - if(*wait < 10) { *wait = 10; } - - for(c = 0; c < *wait;) { - if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { - AT91C_BASE_SSC->SSC_THR = 0x00; // For exact timing! - c++; - } - if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { - volatile DWORD r = AT91C_BASE_SSC->SSC_RHR; - (void)r; - } - WDT_HIT(); + int c; + + FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); + + if (wait) + if(*wait < 10) + *wait = 10; + + for(c = 0; c < *wait;) { + if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { + AT91C_BASE_SSC->SSC_THR = 0x00; // For exact timing! + c++; } - - c = 0; - for(;;) { - if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { - AT91C_BASE_SSC->SSC_THR = cmd[c]; - c++; - if(c >= len) { - break; - } - } - if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { - volatile DWORD r = AT91C_BASE_SSC->SSC_RHR; - (void)r; - } - WDT_HIT(); + if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { + volatile DWORD r = AT91C_BASE_SSC->SSC_RHR; + (void)r; + } + WDT_HIT(); + } + + c = 0; + for(;;) { + if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { + AT91C_BASE_SSC->SSC_THR = cmd[c]; + c++; + if(c >= len) { + break; + } } - *samples = (c + *wait) << 3; + if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { + volatile DWORD r = AT91C_BASE_SSC->SSC_RHR; + (void)r; + } + WDT_HIT(); + } + if (samples) *samples = (c + *wait) << 3; } //----------------------------------------------------------------------------- @@ -1351,11 +1359,11 @@ void ArbitraryFromReader(const BYTE *cmd, int parity, int len) // Code a 7-bit command without parity bit // This is especially for 0x26 and 0x52 (REQA and WUPA) //----------------------------------------------------------------------------- -void ShortFrameFromReader(const BYTE *cmd) +void ShortFrameFromReader(const BYTE bt) { int j; int last; - BYTE b; + BYTE b; ToSendReset(); @@ -1363,7 +1371,7 @@ void ShortFrameFromReader(const BYTE *cmd) Sequence(SEC_Z); last = 0; - b = cmd[0]; + b = bt; for(j = 0; j < 7; j++) { if(b & 1) { // Sequence X @@ -1407,86 +1415,81 @@ void ShortFrameFromReader(const BYTE *cmd) //----------------------------------------------------------------------------- // Prepare reader command to send to FPGA -// +// //----------------------------------------------------------------------------- -void CodeIso14443aAsReader(const BYTE *cmd, int len) +void CodeIso14443aAsReaderPar(const BYTE * cmd, int len, DWORD dwParity) { - int i, j; - int last; - int oddparity; - BYTE b; - - ToSendReset(); - - // Start of Communication (Seq. Z) - Sequence(SEC_Z); - last = 0; - - for(i = 0; i < len; i++) { - // Data bits - b = cmd[i]; - oddparity = 0x01; - for(j = 0; j < 8; j++) { - oddparity ^= (b & 1); - if(b & 1) { - // Sequence X - Sequence(SEC_X); - last = 1; - } else { - if(last == 0) { - // Sequence Z - Sequence(SEC_Z); - } - else { - // Sequence Y - Sequence(SEC_Y); - last = 0; - } - } - b >>= 1; + int i, j; + int last; + BYTE b; + + ToSendReset(); + + // Start of Communication (Seq. Z) + Sequence(SEC_Z); + last = 0; + + // Generate send structure for the data bits + for (i = 0; i < len; i++) { + // Get the current byte to send + b = cmd[i]; + + for (j = 0; j < 8; j++) { + if (b & 1) { + // Sequence X + Sequence(SEC_X); + last = 1; + } else { + if (last == 0) { + // Sequence Z + Sequence(SEC_Z); + } else { + // Sequence Y + Sequence(SEC_Y); + last = 0; } - - // Parity bit - if(oddparity) { - // Sequence X - Sequence(SEC_X); - last = 1; - } else { - if(last == 0) { - // Sequence Z - Sequence(SEC_Z); - } - else { - // Sequence Y - Sequence(SEC_Y); - last = 0; - } - } + } + b >>= 1; } - - // End of Communication - if(last == 0) { - // Sequence Z - Sequence(SEC_Z); - } - else { - // Sequence Y - Sequence(SEC_Y); - last = 0; - } - // Sequence Y - Sequence(SEC_Y); - - // Just to be sure! - Sequence(SEC_Y); - Sequence(SEC_Y); - Sequence(SEC_Y); - - // Convert from last character reference to length - ToSendMax++; + + // Get the parity bit + if ((dwParity >> i) & 0x01) { + // Sequence X + Sequence(SEC_X); + last = 1; + } else { + if (last == 0) { + // Sequence Z + Sequence(SEC_Z); + } else { + // Sequence Y + Sequence(SEC_Y); + last = 0; + } + } + } + + // End of Communication + if (last == 0) { + // Sequence Z + Sequence(SEC_Z); + } else { + // Sequence Y + Sequence(SEC_Y); + last = 0; + } + // Sequence Y + Sequence(SEC_Y); + + // Just to be sure! + Sequence(SEC_Y); + Sequence(SEC_Y); + Sequence(SEC_Y); + + // Convert from last character reference to length + ToSendMax++; } - //----------------------------------------------------------------------------- // Wait a certain time for tag response // If a response is captured return TRUE @@ -1509,7 +1512,7 @@ static BOOL GetIso14443aAnswerFromTag(BYTE *receivedResponse, int maxLen, int *s Demod.state = DEMOD_UNSYNCD; BYTE b; - *elapsed = 0; + if (elapsed) *elapsed = 0; c = 0; for(;;) { @@ -1517,7 +1520,7 @@ static BOOL GetIso14443aAnswerFromTag(BYTE *receivedResponse, int maxLen, int *s if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = 0x00; // To make use of exact timing of next command from reader!! - (*elapsed)++; + if (elapsed) (*elapsed)++; } if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { if(c < 512) { c++; } else { return FALSE; } @@ -1534,7 +1537,51 @@ static BOOL GetIso14443aAnswerFromTag(BYTE *receivedResponse, int maxLen, int *s } } +void ReaderTransmitShort(const BYTE* bt) +{ + int wait = 0; + int samples = 0; + + ShortFrameFromReader(*bt); + + // Select the card + TransmitFor14443a(ToSend, ToSendMax, &samples, &wait); + + // Store reader command in buffer + LogTrace(bt,1,0,GetParity(bt,1),TRUE); +} +void ReaderTransmitPar(BYTE* frame, int len, DWORD par) +{ + int wait = 0; + int samples = 0; + + // This is tied to other size changes + // BYTE* frame_addr = ((BYTE*)BigBuf) + 2024; + + CodeIso14443aAsReaderPar(frame,len,par); + + // Select the card + TransmitFor14443a(ToSend, ToSendMax, &samples, &wait); + + // Store reader command in buffer + LogTrace(frame,len,0,par,TRUE); +} + + +void ReaderTransmit(BYTE* frame, int len) +{ + // Generate parity and redirect + ReaderTransmitPar(frame,len,GetParity(frame,len)); +} + +BOOL ReaderReceive(BYTE* receivedAnswer) +{ + int samples = 0; + if (!GetIso14443aAnswerFromTag(receivedAnswer,100,&samples,0)) return FALSE; + LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE); + return TRUE; +} //----------------------------------------------------------------------------- // Read an ISO 14443a tag. Send out commands and store answers. @@ -1543,211 +1590,100 @@ static BOOL GetIso14443aAnswerFromTag(BYTE *receivedResponse, int maxLen, int *s void ReaderIso14443a(DWORD parameter) { // Anticollision - static const BYTE cmd1[] = { 0x52 }; // or 0x26 - static const BYTE cmd2[] = { 0x93,0x20 }; - // UID = 0x2a,0x69,0x8d,0x43,0x8d, last two bytes are CRC bytes - BYTE cmd3[] = { 0x93,0x70,0x2a,0x69,0x8d,0x43,0x8d,0x52,0x55 }; - - // For Ultralight add an extra anticollission layer -> 95 20 and then 95 70 - - // greg - here we will add our cascade level 2 anticolission and select functions to deal with ultralight // and 7-byte UIDs in generall... - BYTE cmd4[] = {0x95,0x20}; // ask for cascade 2 select - // 95 20 - //BYTE cmd3a[] = { 0x95,0x70,0x2a,0x69,0x8d,0x43,0x8d,0x52,0x55 }; - // 95 70 - - // cascade 2 select - BYTE cmd5[] = { 0x95,0x70,0x2a,0x69,0x8d,0x43,0x8d,0x52,0x55 }; - - - // RATS (request for answer to select) - //BYTE cmd6[] = { 0xe0,0x50,0xbc,0xa5 }; // original RATS - BYTE cmd6[] = { 0xe0,0x21,0xb2,0xc7 }; // Desfire RATS + BYTE wupa[] = { 0x52 }; + BYTE sel_all[] = { 0x93,0x20 }; + BYTE sel_uid[] = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00 }; + BYTE sel_all_c2[] = { 0x95,0x20 }; + BYTE sel_uid_c2[] = { 0x95,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00 }; // Mifare AUTH - BYTE cmd7[] = { 0x60, 0x00, 0x00, 0x00 }; - - int reqaddr = 2024; // was 2024 - tied to other size changes - int reqsize = 60; - - BYTE *req1 = (((BYTE *)BigBuf) + reqaddr); - int req1Len; - - BYTE *req2 = (((BYTE *)BigBuf) + reqaddr + reqsize); - int req2Len; - - BYTE *req3 = (((BYTE *)BigBuf) + reqaddr + (reqsize * 2)); - int req3Len; - -// greg added req 4 & 5 to deal with cascade 2 section - BYTE *req4 = (((BYTE *)BigBuf) + reqaddr + (reqsize * 3)); - int req4Len; - - BYTE *req5 = (((BYTE *)BigBuf) + reqaddr + (reqsize * 4)); - int req5Len; - - BYTE *req6 = (((BYTE *)BigBuf) + reqaddr + (reqsize * 5)); - int req6Len; - - BYTE *req7 = (((BYTE *)BigBuf) + reqaddr + (reqsize * 6)); - int req7Len; - - BYTE *receivedAnswer = (((BYTE *)BigBuf) + 3560); // was 3560 - tied to other size changes - - //BYTE *trace = (BYTE *)BigBuf; - //int traceLen = 0; - //int rsamples = 0; + BYTE mf_auth[] = { 0x60,0x00,0xf5,0x7b }; +// BYTE mf_nr_ar[] = { 0x00,0x00,0x00,0x00 }; + + BYTE* receivedAnswer = (((BYTE *)BigBuf) + 3560); // was 3560 - tied to other size changes traceLen = 0; - memset(trace, 0x44, 2000); // was 2000 - tied to oter size chnages - // setting it to 3000 causes no tag responses to be detected (2900 is ok) - // setting it to 1000 causes no tag responses to be detected - - // Prepare some commands! - ShortFrameFromReader(cmd1); - memcpy(req1, ToSend, ToSendMax); req1Len = ToSendMax; - - CodeIso14443aAsReader(cmd2, sizeof(cmd2)); - memcpy(req2, ToSend, ToSendMax); req2Len = ToSendMax; - - CodeIso14443aAsReader(cmd3, sizeof(cmd3)); - memcpy(req3, ToSend, ToSendMax); req3Len = ToSendMax; - - - CodeIso14443aAsReader(cmd4, sizeof(cmd4)); // 4 is cascade 2 request - memcpy(req4, ToSend, ToSendMax); req4Len = ToSendMax; - - - CodeIso14443aAsReader(cmd5, sizeof(cmd5)); // 5 is cascade 2 select - memcpy(req5, ToSend, ToSendMax); req5Len = ToSendMax; - - - CodeIso14443aAsReader(cmd6, sizeof(cmd6)); - memcpy(req6, ToSend, ToSendMax); req6Len = ToSendMax; - // Setup SSC FpgaSetupSsc(); // Start from off (no field generated) - // Signal field is off with the appropriate LED - LED_D_OFF(); - FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); - SpinDelay(200); + // Signal field is off with the appropriate LED + LED_D_OFF(); + FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); + SpinDelay(200); - SetAdcMuxFor(GPIO_MUXSEL_HIPKD); - FpgaSetupSsc(); + SetAdcMuxFor(GPIO_MUXSEL_HIPKD); + FpgaSetupSsc(); // Now give it time to spin up. - // Signal field is on with the appropriate LED - LED_D_ON(); - FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); + // Signal field is on with the appropriate LED + LED_D_ON(); + FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); SpinDelay(200); LED_A_ON(); LED_B_OFF(); LED_C_OFF(); - int samples = 0; - int tsamples = 0; - int wait = 0; - int elapsed = 0; - - while(1) { - // Send WUPA (or REQA) - TransmitFor14443a(req1, req1Len, &tsamples, &wait); - - // Store reader command in buffer - if (!LogTrace(cmd1,1,0,GetParity(cmd1,1),TRUE)) break; + while(traceLen < TRACE_LENGTH) + { + // Broadcast for a card, WUPA (0x52) will force response from all cards in the field + ReaderTransmitShort(wupa); // Test if the action was cancelled if(BUTTON_PRESS()) { break; } - if(!GetIso14443aAnswerFromTag(receivedAnswer, 100, &samples, &elapsed)) continue; - - // Log the ATQA - if (!LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE)) break; + // Receive the ATQA + if (!ReaderReceive(receivedAnswer)) continue; - // Store reader command in buffer - if (!LogTrace(cmd2,2,0,GetParity(cmd2,2),TRUE)) break; - TransmitFor14443a(req2, req2Len, &samples, &wait); + // Transmit SELECT_ALL + ReaderTransmit(sel_all,sizeof(sel_all)); - if(!GetIso14443aAnswerFromTag(receivedAnswer, 100, &samples, &elapsed)) continue; - - // Log the uid - if (!LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE)) break; + // Receive the UID + if (!ReaderReceive(receivedAnswer)) continue; // Construct SELECT UID command // First copy the 5 bytes (Mifare Classic) after the 93 70 - memcpy(cmd3+2,receivedAnswer,5); + memcpy(sel_uid+2,receivedAnswer,5); // Secondly compute the two CRC bytes at the end - ComputeCrc14443(CRC_14443_A, cmd3, 7, &cmd3[7], &cmd3[8]); - - // Store reader command in buffer - if (!LogTrace(cmd3,9,0,GetParity(cmd5,9),TRUE)) break; - - CodeIso14443aAsReader(cmd3, sizeof(cmd3)); - memcpy(req3, ToSend, ToSendMax); req3Len = ToSendMax; + AppendCrc14443a(sel_uid,7); - // Select the card - TransmitFor14443a(req3, req3Len, &samples, &wait); - if(!GetIso14443aAnswerFromTag(receivedAnswer, 100, &samples, &elapsed)) continue; - - // Log the SAK - if (!LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE)) break; + // Transmit SELECT_UID + ReaderTransmit(sel_uid,sizeof(sel_uid)); + + // Receive the SAK + if (!ReaderReceive(receivedAnswer)) continue; // OK we have selected at least at cascade 1, lets see if first byte of UID was 0x88 in // which case we need to make a cascade 2 request and select - this is a long UID - if (receivedAnswer[0] == 0x88) + // When the UID is not complete, the 3nd bit (from the right) is set in the SAK. + if (receivedAnswer[0] &= 0x04) { - // Do cascade level 2 stuff - /////////////////////////////////////////////////////////////////// - // First issue a '95 20' identify request - // Ask for card UID (part 2) - TransmitFor14443a(req4, req4Len, &tsamples, &wait); - - // Store reader command in buffer - if (!LogTrace(cmd4,2,0,GetParity(cmd4,2),TRUE)) break; - - if(!GetIso14443aAnswerFromTag(receivedAnswer, 100, &samples, &elapsed)) continue; - - ////////////////////////////////////////////////////////////////// - // Then Construct SELECT UID (cascasde 2) command - DbpString("Just about to copy the UID out of the cascade 2 id req"); - // First copy the 5 bytes (Mifare Classic) after the 95 70 - memcpy(cmd5+2,receivedAnswer,5); + // Transmit SELECT_ALL + ReaderTransmit(sel_all_c2,sizeof(sel_all_c2)); + + // Receive the UID + if (!ReaderReceive(receivedAnswer)) continue; + + // Construct SELECT UID command + memcpy(sel_uid_c2+2,receivedAnswer,5); // Secondly compute the two CRC bytes at the end - ComputeCrc14443(CRC_14443_A, cmd4, 7, &cmd5[7], &cmd5[8]); - - // Store reader command in buffer - if (!LogTrace(cmd5,9,0,GetParity(cmd5,9),TRUE)) break; - - CodeIso14443aAsReader(cmd5, sizeof(cmd5)); - memcpy(req5, ToSend, ToSendMax); req5Len = ToSendMax; + AppendCrc14443a(sel_uid_c2,7); - // Select the card - TransmitFor14443a(req4, req4Len, &samples, &wait); - if(!GetIso14443aAnswerFromTag(receivedAnswer, 100, &samples, &elapsed)) continue; + // Transmit SELECT_UID + ReaderTransmit(sel_uid_c2,sizeof(sel_uid_c2)); - // Log the SAK - if (!LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE)) break; + // Receive the SAK + if (!ReaderReceive(receivedAnswer)) continue; } - // Secondly compute the two CRC bytes at the end - ComputeCrc14443(CRC_14443_A, cmd7, 2, &cmd7[2], &cmd7[3]); - CodeIso14443aAsReader(cmd7, sizeof(cmd7)); - memcpy(req7, ToSend, ToSendMax); req7Len = ToSendMax; - - // Send authentication request (Mifare Classic) - TransmitFor14443a(req7, req7Len, &samples, &wait); - // Store reader command in buffer - if (!LogTrace(cmd7,4,0,GetParity(cmd7,4),TRUE)) break; - - if(!GetIso14443aAnswerFromTag(receivedAnswer, 100, &samples, &elapsed)) continue; + // Transmit MIFARE_CLASSIC_AUTH + ReaderTransmit(mf_auth,sizeof(mf_auth)); - // We received probably a random, continue and trace! - if (!LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE)) break; + // Receive the (16 bit) "random" nonce + if (!ReaderReceive(receivedAnswer)) continue; } // Thats it... -- 2.39.2