FIX: this free call still annoys Coverity Scan.

[proxmark3-svn] / armsrc / iso14443a.c

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 8dbe9e81f714fb21c4cff3d43ca43086bfc0ce27..c4298fcb4ae7612c45aa5eb50b11a8b8c609b01c 100644 (file)
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -750,7 +750,7 @@ static void CodeIso14443aAsTagPar(const uint8_t *cmd, uint16_t len, uint8_t *par
 
 static void CodeIso14443aAsTag(const uint8_t *cmd, uint16_t len)
 {
 
 static void CodeIso14443aAsTag(const uint8_t *cmd, uint16_t len)
 {

-       uint8_t par[MAX_PARITY_SIZE];
+       uint8_t par[MAX_PARITY_SIZE] = {0};

        
        GetParity(cmd, len, par);
        CodeIso14443aAsTagPar(cmd, len, par);
        
        GetParity(cmd, len, par);
        CodeIso14443aAsTagPar(cmd, len, par);


@@ -1428,24 +1428,26 @@ void SimulateIso14443aTag(int tagType, int flags, byte_t* data)
 // of bits specified in the delay parameter.
 void PrepareDelayedTransfer(uint16_t delay)
 {
 // of bits specified in the delay parameter.
 void PrepareDelayedTransfer(uint16_t delay)
 {

+       delay &= 0x07;
+       if (!delay) return;
+

        uint8_t bitmask = 0;
        uint8_t bits_to_shift = 0;
        uint8_t bits_shifted = 0;
        uint8_t bitmask = 0;
        uint8_t bits_to_shift = 0;
        uint8_t bits_shifted = 0;

+       uint16_t i = 0;
+
+       for (i = 0; i < delay; ++i)
+               bitmask |= (0x01 << i);

 
 

-       delay &= 0x07;
-       if (delay) {
-               for (uint16_t i = 0; i < delay; i++) {
-                       bitmask |= (0x01 << i);
-               }

                ToSend[++ToSendMax] = 0x00;
                ToSend[++ToSendMax] = 0x00;

-               for (uint16_t i = 0; i < ToSendMax; i++) {
+
+       for (i = 0; i < ToSendMax; ++i) {

                        bits_to_shift = ToSend[i] & bitmask;
                        ToSend[i] = ToSend[i] >> delay;
                        ToSend[i] = ToSend[i] | (bits_shifted << (8 - delay));
                        bits_shifted = bits_to_shift;
                }
        }
                        bits_to_shift = ToSend[i] & bitmask;
                        ToSend[i] = ToSend[i] >> delay;
                        ToSend[i] = ToSend[i] | (bits_shifted << (8 - delay));
                        bits_shifted = bits_to_shift;
                }
        }

-}

 
 
 //-------------------------------------------------------------------------------------
 
 
 //-------------------------------------------------------------------------------------


@@ -1463,18 +1465,27 @@ static void TransmitFor14443a(const uint8_t *cmd, uint16_t len, uint32_t *timing
        uint32_t ThisTransferTime = 0;
 
        if (timing) {
        uint32_t ThisTransferTime = 0;
 
        if (timing) {

-               if(*timing == 0) {                                                                              // Measure time
+
+               if (*timing != 0)
+                       // Delay transfer (fine tuning - up to 7 MF clock ticks)
+                       PrepareDelayedTransfer(*timing & 0x00000007);   
+               else
+                       // Measure time

                        *timing = (GetCountSspClk() + 8) & 0xfffffff8;
                        *timing = (GetCountSspClk() + 8) & 0xfffffff8;

-               } else {
-                       PrepareDelayedTransfer(*timing & 0x00000007);           // Delay transfer (fine tuning - up to 7 MF clock ticks)
-               }
-               if(MF_DBGLEVEL >= 4 && GetCountSspClk() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing");
+

                
                

-               while(GetCountSspClk() < (*timing & 0xfffffff8));               // Delay transfer (multiple of 8 MF clock ticks)
+               if (MF_DBGLEVEL >= 4 && GetCountSspClk() >= (*timing & 0xfffffff8)) 
+                       Dbprintf("TransmitFor14443a: Missed timing");
+               
+               // Delay transfer (multiple of 8 MF clock ticks)
+               while (GetCountSspClk() < (*timing & 0xfffffff8));      
+

                LastTimeProxToAirStart = *timing;
        } else {
                ThisTransferTime = ((MAX(NextTransferTime, GetCountSspClk()) & 0xfffffff8) + 8);
                LastTimeProxToAirStart = *timing;
        } else {
                ThisTransferTime = ((MAX(NextTransferTime, GetCountSspClk()) & 0xfffffff8) + 8);

+

                while(GetCountSspClk() < ThisTransferTime);
                while(GetCountSspClk() < ThisTransferTime);

+

                LastTimeProxToAirStart = ThisTransferTime;
        }
        
                LastTimeProxToAirStart = ThisTransferTime;
        }
        


@@ -1572,7 +1583,7 @@ void CodeIso14443aBitsAsReaderPar(const uint8_t *cmd, uint16_t bits, const uint8
        ToSend[++ToSendMax] = SEC_Y;
 
        // Convert to length of command:
        ToSend[++ToSendMax] = SEC_Y;
 
        // Convert to length of command:

-       ToSendMax++;
+       ++ToSendMax;

 }
 
 //-----------------------------------------------------------------------------
 }
 
 //-----------------------------------------------------------------------------


@@ -1580,7 +1591,8 @@ void CodeIso14443aBitsAsReaderPar(const uint8_t *cmd, uint16_t bits, const uint8
 //-----------------------------------------------------------------------------
 void CodeIso14443aAsReaderPar(const uint8_t *cmd, uint16_t len, const uint8_t *parity)
 {
 //-----------------------------------------------------------------------------
 void CodeIso14443aAsReaderPar(const uint8_t *cmd, uint16_t len, const uint8_t *parity)
 {

-  CodeIso14443aBitsAsReaderPar(cmd, len*8, parity);
+  //CodeIso14443aBitsAsReaderPar(cmd, len*8, parity);
+  CodeIso14443aBitsAsReaderPar(cmd, len<<3, parity);

 }
 
 
 }
 
 


@@ -1703,7 +1715,7 @@ static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen, bool correctionNe
        }
 
        // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
        }
 
        // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:

-       uint8_t fpga_queued_bits = FpgaSendQueueDelay >> 3;
+       uint8_t fpga_queued_bits = FpgaSendQueueDelay >> 3;  // twich /8 ??   >>3, 

        for (i = 0; i <= fpga_queued_bits/8 + 1; ) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                        AT91C_BASE_SSC->SSC_THR = SEC_F;
        for (i = 0; i <= fpga_queued_bits/8 + 1; ) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                        AT91C_BASE_SSC->SSC_THR = SEC_F;


@@ -1838,19 +1850,22 @@ void ReaderTransmitBitsPar(uint8_t* frame, uint16_t bits, uint8_t *par, uint32_t
                LED_A_ON();
   
        // Log reader command in trace buffer
                LED_A_ON();
   
        // Log reader command in trace buffer

-       LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, par, TRUE);
+       //LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, par, TRUE);
+       LogTrace(frame, nbytes(bits), (LastTimeProxToAirStart<<4) + DELAY_ARM2AIR_AS_READER, ((LastTimeProxToAirStart + LastProxToAirDuration)<<4) + DELAY_ARM2AIR_AS_READER, par, TRUE);

 }
 
 void ReaderTransmitPar(uint8_t* frame, uint16_t len, uint8_t *par, uint32_t *timing)
 {
 }
 
 void ReaderTransmitPar(uint8_t* frame, uint16_t len, uint8_t *par, uint32_t *timing)
 {

-  ReaderTransmitBitsPar(frame, len*8, par, timing);
+  //ReaderTransmitBitsPar(frame, len*8, par, timing);
+  ReaderTransmitBitsPar(frame, len<<3, par, timing);

 }
 
 void ReaderTransmitBits(uint8_t* frame, uint16_t len, uint32_t *timing)
 {
   // Generate parity and redirect
   uint8_t par[MAX_PARITY_SIZE] = {0x00};
 }
 
 void ReaderTransmitBits(uint8_t* frame, uint16_t len, uint32_t *timing)
 {
   // Generate parity and redirect
   uint8_t par[MAX_PARITY_SIZE] = {0x00};

-  GetParity(frame, len/8, par);
+  //GetParity(frame, len/8, par);
+  GetParity(frame, len >> 3, par);

   ReaderTransmitBitsPar(frame, len, par, timing);
 }
 
   ReaderTransmitBitsPar(frame, len, par, timing);
 }
 


@@ -1859,7 +1874,8 @@ void ReaderTransmit(uint8_t* frame, uint16_t len, uint32_t *timing)
   // Generate parity and redirect
   uint8_t par[MAX_PARITY_SIZE] = {0x00};
   GetParity(frame, len, par);
   // Generate parity and redirect
   uint8_t par[MAX_PARITY_SIZE] = {0x00};
   GetParity(frame, len, par);

-  ReaderTransmitBitsPar(frame, len*8, par, timing);
+  //ReaderTransmitBitsPar(frame, len*8, par, timing);
+  ReaderTransmitBitsPar(frame, len<<3, par, timing);

 }
 
 int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t *parity)
 }
 
 int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t *parity)


@@ -1867,7 +1883,8 @@ int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t *parit
        if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, offset)) 
                return FALSE;
 
        if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, offset)) 
                return FALSE;
 

-       LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, FALSE);
+       //LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, FALSE);
+       LogTrace(receivedAnswer, Demod.len, (Demod.startTime<<4) - DELAY_AIR2ARM_AS_READER, (Demod.endTime<<4) - DELAY_AIR2ARM_AS_READER, parity, FALSE);

        return Demod.len;
 }
 
        return Demod.len;
 }
 


@@ -1876,7 +1893,8 @@ int ReaderReceive(uint8_t *receivedAnswer, uint8_t *parity)
        if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, 0)) 
                return FALSE;
 
        if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, 0)) 
                return FALSE;
 

-       LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, FALSE);
+       //LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, FALSE);
+       LogTrace(receivedAnswer, Demod.len, (Demod.startTime<<4) - DELAY_AIR2ARM_AS_READER, (Demod.endTime<<4) - DELAY_AIR2ARM_AS_READER, parity, FALSE);

        return Demod.len;
 }
 
        return Demod.len;
 }
 


@@ -2189,17 +2207,63 @@ void ReaderIso14443a(UsbCommand *c)
 int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
 
        if (nt1 == nt2) return 0;
 int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
 
        if (nt1 == nt2) return 0;

-       
+

        uint16_t i;
        uint32_t nttmp1 = nt1;
        uint32_t nttmp2 = nt2;
        
        uint16_t i;
        uint32_t nttmp1 = nt1;
        uint32_t nttmp2 = nt2;
        

-       for (i = 1; i < 0xFFFF; ++i) {
-               nttmp1 = prng_successor(nttmp1, 1);
-               if (nttmp1 == nt2) return i;
+       for (i = 1; i < 0xFFFF; i += 8) {
+               nttmp1 = prng_successor_one(nttmp1); if (nttmp1 == nt2) return i;
+               nttmp2 = prng_successor_one(nttmp2); if (nttmp2 == nt1) return -i;
+
+               nttmp1 = prng_successor_one(nttmp1); if (nttmp1 == nt2) return i+1;
+               nttmp2 = prng_successor_one(nttmp2); if (nttmp2 == nt1) return -i+1;
+
+               nttmp1 = prng_successor_one(nttmp1); if (nttmp1 == nt2) return i+2;
+               nttmp2 = prng_successor_one(nttmp2); if (nttmp2 == nt1) return -i+2;
+
+               nttmp1 = prng_successor_one(nttmp1); if (nttmp1 == nt2) return i+3;
+               nttmp2 = prng_successor_one(nttmp2); if (nttmp2 == nt1) return -i+3;
+
+               nttmp1 = prng_successor_one(nttmp1); if (nttmp1 == nt2) return i+4;
+               nttmp2 = prng_successor_one(nttmp2); if (nttmp2 == nt1) return -i+4;
+
+               nttmp1 = prng_successor_one(nttmp1); if (nttmp1 == nt2) return i+5;
+               nttmp2 = prng_successor_one(nttmp2); if (nttmp2 == nt1) return -i+5;
+
+               nttmp1 = prng_successor_one(nttmp1); if (nttmp1 == nt2) return i+6;
+               nttmp2 = prng_successor_one(nttmp2); if (nttmp2 == nt1) return -i+6;
+
+               nttmp1 = prng_successor_one(nttmp1); if (nttmp1 == nt2) return i+7;
+               nttmp2 = prng_successor_one(nttmp2); if (nttmp2 == nt1) return -i+7;
+
+               nttmp1 = prng_successor_one(nttmp1); if (nttmp1 == nt2) return i+8;
+               nttmp2 = prng_successor_one(nttmp2); if (nttmp2 == nt1) return -i+8;
+/*
+               if ( prng_successor(nttmp1, i) == nt2) return i;
+               if ( prng_successor(nttmp2, i) == nt1) return -i;
+
+               if ( prng_successor(nttmp1, i+2) == nt2) return i+2;
+               if ( prng_successor(nttmp2, i+2) == nt1) return -(i+2);
+
+               if ( prng_successor(nttmp1, i+3) == nt2) return i+3;
+               if ( prng_successor(nttmp2, i+3) == nt1) return -(i+3);
+
+               if ( prng_successor(nttmp1, i+4) == nt2) return i+4;
+               if ( prng_successor(nttmp2, i+4) == nt1) return -(i+4);
+
+               if ( prng_successor(nttmp1, i+5) == nt2) return i+5;
+               if ( prng_successor(nttmp2, i+5) == nt1) return -(i+5);
+
+               if ( prng_successor(nttmp1, i+6) == nt2) return i+6;
+               if ( prng_successor(nttmp2, i+6) == nt1) return -(i+6);
+
+               if ( prng_successor(nttmp1, i+7) == nt2) return i+7;
+               if ( prng_successor(nttmp2, i+7) == nt1) return -(i+7);

 
 

-               nttmp2 = prng_successor(nttmp2, 1);
-               if (nttmp2 == nt1) return -i;
+               if ( prng_successor(nttmp1, i+8) == nt2) return i+8;
+               if ( prng_successor(nttmp2, i+8) == nt1) return -(i+8);
+*/

        }
        
        return(-99999); // either nt1 or nt2 are invalid nonces
        }
        
        return(-99999); // either nt1 or nt2 are invalid nonces


@@ -2230,9 +2294,8 @@ void ReaderMifare(bool first_try, uint8_t block )
        byte_t nt_diff = 0;
        uint8_t par[1] = {0};   // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
        static byte_t par_low = 0;
        byte_t nt_diff = 0;
        uint8_t par[1] = {0};   // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
        static byte_t par_low = 0;

-       bool led_on = TRUE;

        uint8_t uid[10] = {0};
        uint8_t uid[10] = {0};

-       uint32_t cuid = 0;
+       //uint32_t cuid = 0;

 
        uint32_t nt = 0;
        uint32_t previous_nt = 0;
 
        uint32_t nt = 0;
        uint32_t previous_nt = 0;


@@ -2256,17 +2319,11 @@ void ReaderMifare(bool first_try, uint8_t block )
 
        uint16_t unexpected_random = 0;
        uint16_t sync_tries = 0;
 
        uint16_t unexpected_random = 0;
        uint16_t sync_tries = 0;

-       int16_t debug_info_nr = -1;

        uint16_t strategy = 0;
        uint16_t strategy = 0;

-       int32_t debug_info[MAX_STRATEGY+1][NUM_DEBUG_INFOS];
-       uint32_t select_time = 0;

        uint32_t halt_time = 0;
        uint32_t halt_time = 0;

-       //uint8_t caller[7] = {0};      

 
 

-       // init to zero.
-       for (uint16_t i = 0; i < MAX_STRATEGY+1; ++i)
-               for(uint16_t j = 0; j < NUM_DEBUG_INFOS; ++j)
-                       debug_info[i][j] = 0;
+       clear_trace();
+       set_tracing(TRUE);

        
        LED_A_ON();
        LED_B_OFF();
        
        LED_A_ON();
        LED_B_OFF();


@@ -2277,8 +2334,6 @@ void ReaderMifare(bool first_try, uint8_t block )
        
        // free eventually allocated BigBuf memory. We want all for tracing.
        BigBuf_free();
        
        // free eventually allocated BigBuf memory. We want all for tracing.
        BigBuf_free();

-       clear_trace();
-       set_tracing(TRUE);

 
        if (first_try) { 
                sync_time = GetCountSspClk() & 0xfffffff8;
 
        if (first_try) { 
                sync_time = GetCountSspClk() & 0xfffffff8;


@@ -2310,7 +2365,7 @@ void ReaderMifare(bool first_try, uint8_t block )
                        int len = mifare_sendcmd_short(NULL, false, 0x50, 0x00, receivedAnswer, receivedAnswerPar, &halt_time);
 
                        if (len && MF_DBGLEVEL >= 3)
                        int len = mifare_sendcmd_short(NULL, false, 0x50, 0x00, receivedAnswer, receivedAnswerPar, &halt_time);
 
                        if (len && MF_DBGLEVEL >= 3)

-                               Dbprintf("Unexpected response of %d bytes to halt command (additional debugging).\n", len);
+                               Dbprintf("Unexpected response of %d bytes to halt command.", len);

                }
 
                if (strategy == 3) {
                }
 
                if (strategy == 3) {


@@ -2323,61 +2378,32 @@ void ReaderMifare(bool first_try, uint8_t block )
                        WDT_HIT();
                }
                
                        WDT_HIT();
                }
                

-               if (!iso14443a_select_card(uid, NULL, &cuid, true, 0)) {
+               if (!iso14443a_select_card(uid, NULL, NULL, true, 0)) {

                        if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Can't select card\n");
                        continue;
                }
                        if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Can't select card\n");
                        continue;
                }

-
-               select_time = GetCountSspClk() & 0xfffffff8;
-               elapsed_prng_sequences = 1;

                
                

-               if (debug_info_nr == -1) {
-                       
-                       sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
-                       catch_up_cycles = 0;
-                                                                       
-                       // if we missed the sync time already, advance to the next nonce repeat
-                       WDT_HIT();
-                       while(GetCountSspClk() > sync_time) {
-                               ++elapsed_prng_sequences;
-                               sync_time = (sync_time & 0xfffffff8) + sync_cycles;
-                               //sync_time += sync_cycles;
-                               //sync_time &= 0xfffffff8;
-                       }
-                       WDT_HIT();
-                       // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
-                       ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);                   
-                       if (MF_DBGLEVEL == 2) Dbprintf("sync_time %d \n", sync_time);
-                       
-               } else {
-                       // collect some information on tag nonces for debugging:
-                       #define DEBUG_FIXED_SYNC_CYCLES PRNG_SEQUENCE_LENGTH
-                       if (strategy == 0) {
-                               // nonce distances at fixed time after card select:
-                               sync_time = select_time + DEBUG_FIXED_SYNC_CYCLES;
-                       } else if (strategy == 1) {
-                               // nonce distances at fixed time between authentications:
-                               sync_time = sync_time + DEBUG_FIXED_SYNC_CYCLES;
-                       } else if (strategy == 2) {
-                               // nonce distances at fixed time after halt:
-                               sync_time = halt_time + DEBUG_FIXED_SYNC_CYCLES;
-                       } else {
-                               // nonce_distances at fixed time after power on
-                               sync_time = DEBUG_FIXED_SYNC_CYCLES;
-                       }
-                       ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
-               }                       
+               sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
+               catch_up_cycles = 0;
+                                                               
+               // if we missed the sync time already, advance to the next nonce repeat
+               while(GetCountSspClk() > sync_time) {
+                       ++elapsed_prng_sequences;
+                       sync_time += sync_cycles;
+               }
+               // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
+               ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);                   

 
                // Receive the (4 Byte) "random" nonce
                if (!ReaderReceive(receivedAnswer, receivedAnswerPar))
                        continue;
 
 
                // Receive the (4 Byte) "random" nonce
                if (!ReaderReceive(receivedAnswer, receivedAnswerPar))
                        continue;
 

-               previous_nt = nt;
-               nt = bytes_to_num(receivedAnswer, 4);
-

                // Transmit reader nonce with fake par
                ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par, NULL);
 
                // Transmit reader nonce with fake par
                ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par, NULL);
 

+               previous_nt = nt;
+               nt = bytes_to_num(receivedAnswer, 4);
+               

                if (first_try && previous_nt && !nt_attacked) { // we didn't calibrate our clock yet
                        int nt_distance = dist_nt(previous_nt, nt);
                        if (nt_distance == 0) {
                if (first_try && previous_nt && !nt_attacked) { // we didn't calibrate our clock yet
                        int nt_distance = dist_nt(previous_nt, nt);
                        if (nt_distance == 0) {


@@ -2397,22 +2423,16 @@ void ReaderMifare(bool first_try, uint8_t block )
                                        if (strategy > MAX_STRATEGY || MF_DBGLEVEL < 3) {
                                                isOK = -4;                      // Card's PRNG runs at an unexpected frequency or resets unexpectedly
                                                break;
                                        if (strategy > MAX_STRATEGY || MF_DBGLEVEL < 3) {
                                                isOK = -4;                      // Card's PRNG runs at an unexpected frequency or resets unexpectedly
                                                break;

-                                       } else {                                // continue for a while, just to collect some debug info
-                                               ++debug_info_nr;
-                                               debug_info[strategy][debug_info_nr] = nt_distance;                                              
-                                               if (debug_info_nr == NUM_DEBUG_INFOS-1) {
-                                                       ++strategy;
-                                                       debug_info_nr = 0;
-                                               }
+                                       } else {

                                                continue;
                                        }
                                }
                                
                                                continue;
                                        }
                                }
                                

-                               sync_cycles = (sync_cycles - nt_distance/elapsed_prng_sequences);
+                               sync_cycles = (sync_cycles - nt_distance)/elapsed_prng_sequences;

                                if (sync_cycles <= 0)
                                        sync_cycles += PRNG_SEQUENCE_LENGTH;
                                
                                if (sync_cycles <= 0)
                                        sync_cycles += PRNG_SEQUENCE_LENGTH;
                                

-                               if (MF_DBGLEVEL >= 2)
+                               if (MF_DBGLEVEL >= 3)

                                        Dbprintf("calibrating in cycle %d. nt_distance=%d, elapsed_prng_sequences=%d, new sync_cycles: %d\n", i, nt_distance, elapsed_prng_sequences, sync_cycles);
 
                                continue;
                                        Dbprintf("calibrating in cycle %d. nt_distance=%d, elapsed_prng_sequences=%d, new sync_cycles: %d\n", i, nt_distance, elapsed_prng_sequences, sync_cycles);
 
                                continue;


@@ -2435,8 +2455,7 @@ void ReaderMifare(bool first_try, uint8_t block )
                        } else {
                                last_catch_up = catch_up_cycles;
                            consecutive_resyncs = 0;
                        } else {
                                last_catch_up = catch_up_cycles;
                            consecutive_resyncs = 0;

-                       }
-                       sync_cycles += catch_up_cycles;
+                       }               

                        
                        if (consecutive_resyncs < 3) {
                                if (MF_DBGLEVEL >= 3)
                        
                        if (consecutive_resyncs < 3) {
                                if (MF_DBGLEVEL >= 3)


@@ -2454,8 +2473,6 @@ void ReaderMifare(bool first_try, uint8_t block )
                        continue;
                }
  
                        continue;
                }
  

-               consecutive_resyncs = 0;
-               

                // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding
                if (ReaderReceive(receivedAnswer, receivedAnswerPar)) {
                        catch_up_cycles = 8;    // the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer
                // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding
                if (ReaderReceive(receivedAnswer, receivedAnswerPar)) {
                        catch_up_cycles = 8;    // the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer


@@ -2463,9 +2480,6 @@ void ReaderMifare(bool first_try, uint8_t block )
                        if (nt_diff == 0)
                                par_low = par[0] & 0xE0; // there is no need to check all parities for other nt_diff. Parity Bits for mf_nr_ar[0..2] won't change
 
                        if (nt_diff == 0)
                                par_low = par[0] & 0xE0; // there is no need to check all parities for other nt_diff. Parity Bits for mf_nr_ar[0..2] won't change
 

-                       led_on = !led_on;
-                       if(led_on) LED_B_ON(); else LED_B_OFF();
-

                        par_list[nt_diff] = SwapBits(par[0], 8);
                        ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
 
                        par_list[nt_diff] = SwapBits(par[0], 8);
                        ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
 


@@ -2478,6 +2492,7 @@ void ReaderMifare(bool first_try, uint8_t block )
                        nt_diff = (nt_diff + 1) & 0x07;
                        mf_nr_ar[3] = (mf_nr_ar[3] & 0x1F) | (nt_diff << 5);
                        par[0] = par_low;
                        nt_diff = (nt_diff + 1) & 0x07;
                        mf_nr_ar[3] = (mf_nr_ar[3] & 0x1F) | (nt_diff << 5);
                        par[0] = par_low;

+                       

                } else {
                        if (nt_diff == 0 && first_try) {
                                par[0]++;
                } else {
                        if (nt_diff == 0 && first_try) {
                                par[0]++;


@@ -2489,17 +2504,13 @@ void ReaderMifare(bool first_try, uint8_t block )
                                par[0] = ((par[0] & 0x1F) + 1) | par_low;
                        }
                }
                                par[0] = ((par[0] & 0x1F) + 1) | par_low;
                        }
                }

+               
+               consecutive_resyncs = 0;

        }
 
        mf_nr_ar[3] &= 0x1F;
 
        WDT_HIT();
        }
 
        mf_nr_ar[3] &= 0x1F;
 
        WDT_HIT();

-
-       if (isOK == -4) {
-               for (uint16_t i = 0; i < MAX_STRATEGY+1; ++i)
-                       for(uint16_t j = 0; j < NUM_DEBUG_INFOS; ++j)
-                               Dbprintf("info[%d][%d] = %d", i, j, debug_info[i][j]);
-       }

        
        // reset sync_time.
        if ( isOK == 1) {
        
        // reset sync_time.
        if ( isOK == 1) {