Added a comment

[proxmark3-svn] / armsrc / iso14443a.c

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 7c1db14ba842a3067f808fd09a0fffa71898d455..56afaeb84931dd3d1ee350576de0436c536eca4b 100644 (file)
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -898,13 +898,21 @@ static int GetIso14443aCommandFromReader(uint8_t *received, int *len, int maxLen
         }
     }
 }
         }
     }
 }

+

 static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, int correctionNeeded);
 static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, int correctionNeeded);

+int EmSend4bitEx(uint8_t resp, int correctionNeeded);
+int EmSend4bit(uint8_t resp);
+int EmSendCmdExPar(uint8_t *resp, int respLen, int correctionNeeded, uint32_t par);
+int EmSendCmdExPar(uint8_t *resp, int respLen, int correctionNeeded, uint32_t par);
+int EmSendCmdEx(uint8_t *resp, int respLen, int correctionNeeded);
+int EmSendCmd(uint8_t *resp, int respLen);
+int EmSendCmdPar(uint8_t *resp, int respLen, uint32_t par);

 
 //-----------------------------------------------------------------------------
 // Main loop of simulated tag: receive commands from reader, decide what
 // response to send, and send it.
 //-----------------------------------------------------------------------------
 
 //-----------------------------------------------------------------------------
 // Main loop of simulated tag: receive commands from reader, decide what
 // response to send, and send it.
 //-----------------------------------------------------------------------------

-void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
+void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)

 {
   // Enable and clear the trace
        tracing = TRUE;
 {
   // Enable and clear the trace
        tracing = TRUE;


@@ -985,7 +993,7 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
        uint8_t response6[] = { 0x03, 0x3B, 0x00, 0x00, 0x00 }; // dummy ATS (pseudo-ATR), answer to RATS
        ComputeCrc14443(CRC_14443_A, response6, 3, &response6[3], &response6[4]);
 
        uint8_t response6[] = { 0x03, 0x3B, 0x00, 0x00, 0x00 }; // dummy ATS (pseudo-ATR), answer to RATS
        ComputeCrc14443(CRC_14443_A, response6, 3, &response6[3], &response6[4]);
 

-       uint8_t *resp;
+       uint8_t *resp = NULL;

        int respLen;
 
   // Longest possible response will be 16 bytes + 2 CRC = 18 bytes
        int respLen;
 
   // Longest possible response will be 16 bytes + 2 CRC = 18 bytes


@@ -1024,7 +1032,7 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
 
        // Response to a read request - not implemented atm
        uint8_t *resp4 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + (166*4));
 
        // Response to a read request - not implemented atm
        uint8_t *resp4 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + (166*4));

-       int resp4Len;
+//     int resp4Len;

 
        // Authenticate response - nonce
        uint8_t *resp5 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + (166*5));
 
        // Authenticate response - nonce
        uint8_t *resp5 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + (166*5));


@@ -1048,7 +1056,7 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
        int cmdsRecvd = 0;
        uint8_t* respdata = NULL;
        int respsize = 0;
        int cmdsRecvd = 0;
        uint8_t* respdata = NULL;
        int respsize = 0;

-       uint8_t nack = 0x04;
+//     uint8_t nack = 0x04;

 
        memset(receivedCmd, 0x44, RECV_CMD_SIZE);
 
 
        memset(receivedCmd, 0x44, RECV_CMD_SIZE);
 


@@ -1077,7 +1085,7 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
 
        // Strange answer is an example of rare message size (3 bits)
        CodeStrangeAnswerAsTag();
 
        // Strange answer is an example of rare message size (3 bits)
        CodeStrangeAnswerAsTag();

-       memcpy(resp4, ToSend, ToSendMax); resp4Len = ToSendMax;
+       memcpy(resp4, ToSend, ToSendMax);// resp4Len = ToSendMax;

 
        // Authentication answer (random nonce)
        CodeIso14443aAsTag(response5, sizeof(response5));
 
        // Authentication answer (random nonce)
        CodeIso14443aAsTag(response5, sizeof(response5));


@@ -1100,6 +1108,11 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
                        DbpString("button press");
                        break;
                }
                        DbpString("button press");
                        break;
                }

+    
+    if (tracing) {
+                       LogTrace(receivedCmd,len, 0, Uart.parityBits, TRUE);
+    }
+    

                // doob - added loads of debug strings so we can see what the reader is saying to us during the sim as hi14alist is not populated
                // Okay, look at the command now.
                lastorder = order;
                // doob - added loads of debug strings so we can see what the reader is saying to us during the sim as hi14alist is not populated
                // Okay, look at the command now.
                lastorder = order;


@@ -1128,12 +1141,15 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
                        respdata = response3a;
                        respsize = sizeof(response3a);
                } else if(receivedCmd[0] == 0x30) {     // Received a (plain) READ
                        respdata = response3a;
                        respsize = sizeof(response3a);
                } else if(receivedCmd[0] == 0x30) {     // Received a (plain) READ

-                       resp = resp4; respLen = resp4Len; order = 4; // Do nothing
+//                     resp = resp4; respLen = resp4Len; order = 4; // Do nothing
+//                     respdata = &nack;
+//                     respsize = sizeof(nack); // 4-bit answer
+      EmSendCmdEx(data+(4*receivedCmd[0]),16,false);

                        Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]);
                        Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]);

-                       respdata = &nack;
-                       respsize = sizeof(nack); // 4-bit answer
+      // We already responded, do not send anything with the EmSendCmd14443aRaw() that is called below
+      respLen = 0;

                } else if(receivedCmd[0] == 0x50) {     // Received a HALT
                } else if(receivedCmd[0] == 0x50) {     // Received a HALT

-                       DbpString("Reader requested we HALT!:");
+//                     DbpString("Reader requested we HALT!:");

                        // Do not respond
                        resp = resp1; respLen = 0; order = 0;
                        respdata = NULL;
                        // Do not respond
                        resp = resp1; respLen = 0; order = 0;
                        respdata = NULL;


@@ -1147,16 +1163,19 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
                        respdata = response6;
                        respsize = sizeof(response6);
                } else {
                        respdata = response6;
                        respsize = sizeof(response6);
                } else {

-                       // Never seen this command before
-                       Dbprintf("Received (len=%d): %02x %02x %02x %02x %02x %02x %02x %02x %02x",
-                       len,
-                       receivedCmd[0], receivedCmd[1], receivedCmd[2],
-                       receivedCmd[3], receivedCmd[4], receivedCmd[5],
-                       receivedCmd[6], receivedCmd[7], receivedCmd[8]);
-                       // Do not respond
-                       resp = resp1; respLen = 0; order = 0;
-                       respdata = NULL;
-                       respsize = 0;
+      if (order == 7 && len ==8) {
+        uint32_t nr = bytes_to_num(receivedCmd,4);
+        uint32_t ar = bytes_to_num(receivedCmd+4,4);
+        Dbprintf("Auth attempt {nr}{ar}: %08x %08x",nr,ar);
+      } else {
+        // Never seen this command before
+        Dbprintf("Received unknown command (len=%d):",len);
+        Dbhexdump(len,receivedCmd,false);
+      }
+      // Do not respond
+      resp = resp1; respLen = 0; order = 0;
+      respdata = NULL;
+      respsize = 0;

                }
 
                // Count number of wakeups received after a halt
                }
 
                // Count number of wakeups received after a halt


@@ -1183,7 +1202,6 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
                }
                
                if (tracing) {
                }
                
                if (tracing) {

-                       LogTrace(receivedCmd,len, 0, Uart.parityBits, TRUE);

                        if (respdata != NULL) {
                                LogTrace(respdata,respsize, 0, SwapBits(GetParity(respdata,respsize),respsize), FALSE);
                        }
                        if (respdata != NULL) {
                                LogTrace(respdata,respsize, 0, SwapBits(GetParity(respdata,respsize),respsize), FALSE);
                        }


@@ -1244,68 +1262,9 @@ static void TransmitFor14443a(const uint8_t *cmd, int len, int *samples, int *wa
 }
 
 //-----------------------------------------------------------------------------
 }
 
 //-----------------------------------------------------------------------------

-// Code a 7-bit command without parity bit
-// This is especially for 0x26 and 0x52 (REQA and WUPA)
+// Prepare reader command (in bits, support short frames) to send to FPGA

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

-void ShortFrameFromReader(const uint8_t bt)
-{
-       int j;
-       int last;
-  uint8_t b;
-
-       ToSendReset();
-
-       // Start of Communication (Seq. Z)
-       ToSend[++ToSendMax] = SEC_Z;
-       last = 0;
-
-       b = bt;
-       for(j = 0; j < 7; j++) {
-               if(b & 1) {
-                       // Sequence X
-                       ToSend[++ToSendMax] = SEC_X;
-                       last = 1;
-               } else {
-                       if(last == 0) {
-                               // Sequence Z
-                               ToSend[++ToSendMax] = SEC_Z;
-                       }
-                       else {
-                               // Sequence Y
-                               ToSend[++ToSendMax] = SEC_Y;
-                               last = 0;
-                       }
-               }
-               b >>= 1;
-       }
-
-       // End of Communication
-       if(last == 0) {
-               // Sequence Z
-               ToSend[++ToSendMax] = SEC_Z;
-       }
-       else {
-               // Sequence Y
-               ToSend[++ToSendMax] = SEC_Y;
-               last = 0;
-       }
-       // Sequence Y
-       ToSend[++ToSendMax] = SEC_Y;
-
-       // Just to be sure!
-       ToSend[++ToSendMax] = SEC_Y;
-       ToSend[++ToSendMax] = SEC_Y;
-       ToSend[++ToSendMax] = SEC_Y;
-
-    // Convert from last character reference to length
-    ToSendMax++;
-}
-
-//-----------------------------------------------------------------------------
-// Prepare reader command to send to FPGA
-//
-//-----------------------------------------------------------------------------
-void CodeIso14443aAsReaderPar(const uint8_t * cmd, int len, uint32_t dwParity)
+void CodeIso14443aBitsAsReaderPar(const uint8_t * cmd, int bits, uint32_t dwParity)

 {
   int i, j;
   int last;
 {
   int i, j;
   int last;


@@ -1317,12 +1276,14 @@ void CodeIso14443aAsReaderPar(const uint8_t * cmd, int len, uint32_t dwParity)
   ToSend[++ToSendMax] = SEC_Z;
   last = 0;
 
   ToSend[++ToSendMax] = SEC_Z;
   last = 0;
 

+  size_t bytecount = nbytes(bits);

   // Generate send structure for the data bits
   // Generate send structure for the data bits

-  for (i = 0; i < len; i++) {
+  for (i = 0; i < bytecount; i++) {

     // Get the current byte to send
     b = cmd[i];
     // Get the current byte to send
     b = cmd[i];

+    size_t bitsleft = MIN((bits-(i*8)),8);

 
 

-    for (j = 0; j < 8; j++) {
+    for (j = 0; j < bitsleft; j++) {

       if (b & 1) {
         // Sequence X
          ToSend[++ToSendMax] = SEC_X;
       if (b & 1) {
         // Sequence X
          ToSend[++ToSendMax] = SEC_X;


@@ -1340,19 +1301,22 @@ void CodeIso14443aAsReaderPar(const uint8_t * cmd, int len, uint32_t dwParity)
       b >>= 1;
     }
 
       b >>= 1;
     }
 

-    // Get the parity bit
-    if ((dwParity >> i) & 0x01) {
-      // Sequence X
-       ToSend[++ToSendMax] = SEC_X;
-      last = 1;
-    } else {
-      if (last == 0) {
-        // Sequence Z
-         ToSend[++ToSendMax] = SEC_Z;
+    // Only transmit (last) parity bit if we transmitted a complete byte
+    if (j == 8) {
+      // Get the parity bit
+      if ((dwParity >> i) & 0x01) {
+        // Sequence X
+        ToSend[++ToSendMax] = SEC_X;
+        last = 1;

       } else {
       } else {

-        // Sequence Y
-         ToSend[++ToSendMax] = SEC_Y;
-        last = 0;
+        if (last == 0) {
+          // Sequence Z
+          ToSend[++ToSendMax] = SEC_Z;
+        } else {
+          // Sequence Y
+          ToSend[++ToSendMax] = SEC_Y;
+          last = 0;
+        }

       }
     }
   }
       }
     }
   }


@@ -1378,6 +1342,14 @@ void CodeIso14443aAsReaderPar(const uint8_t * cmd, int len, uint32_t dwParity)
   ToSendMax++;
 }
 
   ToSendMax++;
 }
 

+//-----------------------------------------------------------------------------
+// Prepare reader command to send to FPGA
+//-----------------------------------------------------------------------------
+void CodeIso14443aAsReaderPar(const uint8_t * cmd, int len, uint32_t dwParity)
+{
+  CodeIso14443aBitsAsReaderPar(cmd,len*8,dwParity);
+}
+

 //-----------------------------------------------------------------------------
 // Wait for commands from reader
 // Stop when button is pressed (return 1) or field was gone (return 2)
 //-----------------------------------------------------------------------------
 // Wait for commands from reader
 // Stop when button is pressed (return 1) or field was gone (return 2)


@@ -1543,7 +1515,7 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, int maxLen, int
        // Signal field is on with the appropriate LED
        LED_D_ON();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_LISTEN);
        // Signal field is on with the appropriate LED
        LED_D_ON();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_LISTEN);

-
+       

        // Now get the answer from the card
        Demod.output = receivedResponse;
        Demod.len = 0;
        // Now get the answer from the card
        Demod.output = receivedResponse;
        Demod.len = 0;


@@ -1575,43 +1547,33 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, int maxLen, int
        }
 }
 
        }
 }
 

-void ReaderTransmitShort(const uint8_t* bt)
-{
-  int wait = 0;
-  int samples = 0;
-
-  ShortFrameFromReader(*bt);
-
-  // Select the card
-  TransmitFor14443a(ToSend, ToSendMax, &samples, &wait);
-
-  // Store reader command in buffer
-  if (tracing) LogTrace(bt,1,0,GetParity(bt,1),TRUE);
-}
-
-void ReaderTransmitPar(uint8_t* frame, int len, uint32_t par)
+void ReaderTransmitBitsPar(uint8_t* frame, int bits, uint32_t par)

 {
   int wait = 0;
   int samples = 0;
 {
   int wait = 0;
   int samples = 0;

-
+  

   // This is tied to other size changes
   //   uint8_t* frame_addr = ((uint8_t*)BigBuf) + 2024;
   // This is tied to other size changes
   //   uint8_t* frame_addr = ((uint8_t*)BigBuf) + 2024;

-  CodeIso14443aAsReaderPar(frame,len,par);
-
+  CodeIso14443aBitsAsReaderPar(frame,bits,par);
+  

   // Select the card
   TransmitFor14443a(ToSend, ToSendMax, &samples, &wait);
   if(trigger)
        LED_A_ON();
   // Select the card
   TransmitFor14443a(ToSend, ToSendMax, &samples, &wait);
   if(trigger)
        LED_A_ON();

-
+  

   // Store reader command in buffer
   // Store reader command in buffer

-  if (tracing) LogTrace(frame,len,0,par,TRUE);
+  if (tracing) LogTrace(frame,nbytes(bits),0,par,TRUE);

 }
 
 }
 

+void ReaderTransmitPar(uint8_t* frame, int len, uint32_t par)
+{
+  ReaderTransmitBitsPar(frame,len*8,par);
+}

 
 void ReaderTransmit(uint8_t* frame, int len)
 {
   // Generate parity and redirect
 
 void ReaderTransmit(uint8_t* frame, int len)
 {
   // Generate parity and redirect

-  ReaderTransmitPar(frame,len,GetParity(frame,len));
+  ReaderTransmitBitsPar(frame,len*8,GetParity(frame,len));

 }
 
 int ReaderReceive(uint8_t* receivedAnswer)
 }
 
 int ReaderReceive(uint8_t* receivedAnswer)


@@ -1637,26 +1599,26 @@ int ReaderReceivePar(uint8_t* receivedAnswer, uint32_t * parptr)
  * fills the uid pointer unless NULL
  * fills resp_data unless NULL */
 int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, uint32_t* cuid_ptr) {
  * fills the uid pointer unless NULL
  * fills resp_data unless NULL */
 int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, uint32_t* cuid_ptr) {

-       uint8_t wupa[]       = { 0x52 };  // 0x26 - REQA  0x52 - WAKE-UP
-       uint8_t sel_all[]    = { 0x93,0x20 };
-       uint8_t sel_uid[]    = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
-       uint8_t rats[]       = { 0xE0,0x80,0x00,0x00 }; // FSD=256, FSDI=8, CID=0
-       uint8_t* resp = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);     // was 3560 - tied to other size changes
+  uint8_t wupa[]       = { 0x52 };  // 0x26 - REQA  0x52 - WAKE-UP
+  uint8_t sel_all[]    = { 0x93,0x20 };
+  uint8_t sel_uid[]    = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
+  uint8_t rats[]       = { 0xE0,0x80,0x00,0x00 }; // FSD=256, FSDI=8, CID=0
+  uint8_t* resp = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);  // was 3560 - tied to other size changes

   byte_t uid_resp[4];
   size_t uid_resp_len;
 
   byte_t uid_resp[4];
   size_t uid_resp_len;
 

-       uint8_t sak = 0x04; // cascade uid
-       int cascade_level = 0;
-       int len;
+  uint8_t sak = 0x04; // cascade uid
+  int cascade_level = 0;
+  int len;

         
         

-       // Broadcast for a card, WUPA (0x52) will force response from all cards in the field
-       ReaderTransmitShort(wupa);
-       // Receive the ATQA
-       if(!ReaderReceive(resp)) return 0;
+  // Broadcast for a card, WUPA (0x52) will force response from all cards in the field
+    ReaderTransmitBitsPar(wupa,7,0);
+  // Receive the ATQA
+  if(!ReaderReceive(resp)) return 0;

 //  Dbprintf("atqa: %02x %02x",resp[0],resp[1]);
 //  Dbprintf("atqa: %02x %02x",resp[0],resp[1]);

-  
-       if(p_hi14a_card) {
-               memcpy(p_hi14a_card->atqa, resp, 2);
+
+  if(p_hi14a_card) {
+    memcpy(p_hi14a_card->atqa, resp, 2);

     p_hi14a_card->uidlen = 0;
     memset(p_hi14a_card->uid,0,10);
   }
     p_hi14a_card->uidlen = 0;
     memset(p_hi14a_card->uid,0,10);
   }


@@ -1666,19 +1628,18 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u
     memset(uid_ptr,0,10);
   }
 
     memset(uid_ptr,0,10);
   }
 

-       // OK we will select 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
-       // While the UID is not complete, the 3nd bit (from the right) is set in the SAK.
-       for(; sak & 0x04; cascade_level++)
-       {
-               // SELECT_* (L1: 0x93, L2: 0x95, L3: 0x97)
-               sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2;
+  // OK we will select 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
+  // While the UID is not complete, the 3nd bit (from the right) is set in the SAK.
+  for(; sak & 0x04; cascade_level++) {
+    // SELECT_* (L1: 0x93, L2: 0x95, L3: 0x97)
+    sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2;

 
 

-               // SELECT_ALL
-               ReaderTransmit(sel_all,sizeof(sel_all));
-               if (!ReaderReceive(resp)) return 0;
+    // SELECT_ALL
+    ReaderTransmit(sel_all,sizeof(sel_all));
+    if (!ReaderReceive(resp)) return 0;

     
     

-    // First backup the current uid 
+    // First backup the current uid

     memcpy(uid_resp,resp,4);
     uid_resp_len = 4;
     //    Dbprintf("uid: %02x %02x %02x %02x",uid_resp[0],uid_resp[1],uid_resp[2],uid_resp[3]);
     memcpy(uid_resp,resp,4);
     uid_resp_len = 4;
     //    Dbprintf("uid: %02x %02x %02x %02x",uid_resp[0],uid_resp[1],uid_resp[2],uid_resp[3]);


@@ -1688,20 +1649,20 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u
       *cuid_ptr = bytes_to_num(uid_resp, 4);
     }
 
       *cuid_ptr = bytes_to_num(uid_resp, 4);
     }
 

-               // Construct SELECT UID command
+    // Construct SELECT UID command

                memcpy(sel_uid+2,resp,5);
                memcpy(sel_uid+2,resp,5);

-               AppendCrc14443a(sel_uid,7);
-               ReaderTransmit(sel_uid,sizeof(sel_uid));
+    AppendCrc14443a(sel_uid,7);
+    ReaderTransmit(sel_uid,sizeof(sel_uid));

 
 

-               // Receive the SAK
-               if (!ReaderReceive(resp)) return 0;
-               sak = resp[0];
+    // Receive the SAK
+    if (!ReaderReceive(resp)) return 0;
+    sak = resp[0];

 
     // Test if more parts of the uid are comming
     if ((sak & 0x04) && uid_resp[0] == 0x88) {
       // Remove first byte, 0x88 is not an UID byte, it CT, see page 3 of:
       // http://www.nxp.com/documents/application_note/AN10927.pdf
 
     // Test if more parts of the uid are comming
     if ((sak & 0x04) && uid_resp[0] == 0x88) {
       // Remove first byte, 0x88 is not an UID byte, it CT, see page 3 of:
       // http://www.nxp.com/documents/application_note/AN10927.pdf

-      memcpy(uid_ptr, uid_ptr + 1, 3);
+      memcpy(uid_resp, uid_resp + 1, 3);

       uid_resp_len = 3;
     }
     
       uid_resp_len = 3;
     }
     


@@ -1713,31 +1674,31 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u
       memcpy(p_hi14a_card->uid + (cascade_level*3), uid_resp, uid_resp_len);
       p_hi14a_card->uidlen += uid_resp_len;
     }
       memcpy(p_hi14a_card->uid + (cascade_level*3), uid_resp, uid_resp_len);
       p_hi14a_card->uidlen += uid_resp_len;
     }

-       }
+  }

 
 

-       if(p_hi14a_card) {
-               p_hi14a_card->sak = sak;
-               p_hi14a_card->ats_len = 0;
-       }
+  if(p_hi14a_card) {
+    p_hi14a_card->sak = sak;
+    p_hi14a_card->ats_len = 0;
+  }

 
 

-       if( (sak & 0x20) == 0) {
-               return 2; // non iso14443a compliant tag
+  if( (sak & 0x20) == 0) {
+    return 2; // non iso14443a compliant tag

   }
 
   }
 

-       // Request for answer to select
-       if(p_hi14a_card) {  // JCOP cards - if reader sent RATS then there is no MIFARE session at all!!!
-               AppendCrc14443a(rats, 2);
-               ReaderTransmit(rats, sizeof(rats));
-               
-               if (!(len = ReaderReceive(resp))) return 0;
-               
-               memcpy(p_hi14a_card->ats, resp, sizeof(p_hi14a_card->ats));
-               p_hi14a_card->ats_len = len;
-       }
+  // Request for answer to select
+  AppendCrc14443a(rats, 2);
+  ReaderTransmit(rats, sizeof(rats));
+
+  if (!(len = ReaderReceive(resp))) return 0;
+
+  if(p_hi14a_card) {
+    memcpy(p_hi14a_card->ats, resp, sizeof(p_hi14a_card->ats));
+    p_hi14a_card->ats_len = len;
+  }

        
        

-       // reset the PCB block number
-       iso14_pcb_blocknum = 0;
-       return 1;
+  // reset the PCB block number
+  iso14_pcb_blocknum = 0;
+  return 1;

 }
 
 void iso14443a_setup() {
 }
 
 void iso14443a_setup() {


@@ -1850,87 +1811,223 @@ void ReaderIso14443a(UsbCommand * c)
        LEDsoff();
 }
 
        LEDsoff();
 }
 

+
+// prepare the Mifare AUTH transfer with an added necessary delay.
+void PrepareDelayedAuthTransfer(uint8_t* frame, int len, uint16_t delay)
+{
+       CodeIso14443aBitsAsReaderPar(frame, len*8, GetParity(frame,len));
+
+       uint8_t bitmask = 0;
+       uint8_t bits_to_shift = 0;
+       uint8_t bits_shifted = 0;
+       
+       if (delay) {
+               for (uint16_t i = 0; i < delay; i++) {
+                       bitmask |= (0x01 << i);
+               }
+               ToSend[++ToSendMax] = 0x00;
+               for (uint16_t 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;
+               }
+       }
+}
+
+
+
+// Determine the distance between two nonces.
+// Assume that the difference is small, but we don't know which is first.
+// Therefore try in alternating directions.
+int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
+
+       uint16_t i;
+       uint32_t nttmp1, nttmp2;
+
+       if (nt1 == nt2) return 0;
+
+       nttmp1 = nt1;
+       nttmp2 = nt2;
+       
+       for (i = 1; i < 32768; i++) {
+               nttmp1 = prng_successor(nttmp1, 1);
+               if (nttmp1 == nt2) return i;
+               nttmp2 = prng_successor(nttmp2, 1);
+                       if (nttmp2 == nt1) return -i;
+               }
+       
+       return(-99999); // either nt1 or nt2 are invalid nonces
+}
+
+

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

-// Read an ISO 14443a tag. Send out commands and store answers.
-//
+// Recover several bits of the cypher stream. This implements (first stages of)
+// the algorithm described in "The Dark Side of Security by Obscurity and
+// Cloning MiFare Classic Rail and Building Passes, Anywhere, Anytime"
+// (article by Nicolas T. Courtois, 2009)

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

-void ReaderMifare(uint32_t parameter)
+void ReaderMifare(bool first_try)

 {
        // Mifare AUTH
        uint8_t mf_auth[]    = { 0x60,0x00,0xf5,0x7b };
        uint8_t mf_nr_ar[]   = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
 {
        // Mifare AUTH
        uint8_t mf_auth[]    = { 0x60,0x00,0xf5,0x7b };
        uint8_t mf_nr_ar[]   = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };

+       static uint8_t mf_nr_ar3;

 
 

-       uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);   // was 3560 - tied to other size changes
+       uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);

        traceLen = 0;
        tracing = false;
 
        traceLen = 0;
        tracing = false;
 

-       iso14443a_setup();
-
-       LED_A_ON();
-       LED_B_OFF();
-       LED_C_OFF();
-

        byte_t nt_diff = 0;
        byte_t nt_diff = 0;

-       LED_A_OFF();

        byte_t par = 0;
        //byte_t par_mask = 0xff;
        byte_t par = 0;
        //byte_t par_mask = 0xff;

-       byte_t par_low = 0;
-       int led_on = TRUE;
-       uint8_t uid[8];
+       static byte_t par_low = 0;
+       bool led_on = TRUE;
+       uint8_t uid[10];

        uint32_t cuid;
 
        uint32_t cuid;
 

-       tracing = FALSE;
-       byte_t nt[4] = {0,0,0,0};
-       byte_t nt_attacked[4], nt_noattack[4];
+       uint32_t nt, previous_nt;
+       static uint32_t nt_attacked = 0;

        byte_t par_list[8] = {0,0,0,0,0,0,0,0};
        byte_t ks_list[8] = {0,0,0,0,0,0,0,0};
        byte_t par_list[8] = {0,0,0,0,0,0,0,0};
        byte_t ks_list[8] = {0,0,0,0,0,0,0,0};

-       num_to_bytes(parameter, 4, nt_noattack);
-       int isOK = 0, isNULL = 0;

 
 

-       while(TRUE)
-       {
-               LED_C_OFF();
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-               SpinDelay(50);
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
-               LED_C_ON();
-               SpinDelay(2);
+       static uint32_t sync_time;
+       static uint32_t sync_cycles;
+       int catch_up_cycles = 0;
+       int last_catch_up = 0;
+       uint16_t consecutive_resyncs = 0;
+       int isOK = 0;
+
+
+
+       if (first_try) { 
+               StartCountMifare();
+               mf_nr_ar3 = 0;
+               iso14443a_setup();
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN); // resets some FPGA internal registers
+               while((GetCountMifare() & 0xffff0000) != 0x10000);              // wait for counter to reset and "warm up" 
+               while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME);              // wait for ssp_frame to be low
+               while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME));   // sync on rising edge of ssp_frame
+               sync_time = GetCountMifare();
+               sync_cycles = 65536;                                                                    // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
+               nt_attacked = 0;
+               nt = 0;
+               par = 0;
+       }
+       else {
+               // we were unsuccessful on a previous call. Try another READER nonce (first 3 parity bits remain the same)
+               // nt_attacked = prng_successor(nt_attacked, 1);
+               mf_nr_ar3++;
+               mf_nr_ar[3] = mf_nr_ar3;
+               par = par_low;
+       }
+
+       LED_A_ON();
+       LED_B_OFF();
+       LED_C_OFF();
+       
+  
+       for(uint16_t i = 0; TRUE; i++) {
+               
+               WDT_HIT();

 
                // Test if the action was cancelled
                if(BUTTON_PRESS()) {
                        break;
                }
 
                // Test if the action was cancelled
                if(BUTTON_PRESS()) {
                        break;
                }

+               
+               LED_C_ON();
+
+               if(!iso14443a_select_card(uid, NULL, &cuid)) {
+                       continue;
+               }
+
+               //keep the card active
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);

 
 

-               if(!iso14443a_select_card(uid, NULL, &cuid)) continue;
+               PrepareDelayedAuthTransfer(mf_auth, sizeof(mf_auth), (sync_cycles + catch_up_cycles) & 0x00000007);

 
 

+               sync_time = sync_time + ((sync_cycles + catch_up_cycles) & 0xfffffff8);
+               catch_up_cycles = 0;
+
+               // if we missed the sync time already, advance to the next nonce repeat
+               while(GetCountMifare() > sync_time) {
+                       sync_time = sync_time + (sync_cycles & 0xfffffff8);
+               }
+
+               // now sync. After syncing, the following Classic Auth will return the same tag nonce (mostly)
+               while(GetCountMifare() < sync_time);
+               

                // Transmit MIFARE_CLASSIC_AUTH
                // Transmit MIFARE_CLASSIC_AUTH

-               ReaderTransmit(mf_auth, sizeof(mf_auth));
+               int samples = 0;
+               int wait = 0;
+               TransmitFor14443a(ToSend, ToSendMax, &samples, &wait);

 
 

-               // Receive the (16 bit) "random" nonce
-               if (!ReaderReceive(receivedAnswer)) continue;
-               memcpy(nt, receivedAnswer, 4);
+               // Receive the (4 Byte) "random" nonce
+               if (!ReaderReceive(receivedAnswer)) {
+                       continue;
+                 }

 
 

-               // Transmit reader nonce and reader answer
-               ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar),par);
+ 
+               previous_nt = nt;
+               nt = bytes_to_num(receivedAnswer, 4);

 
 

-               // Receive 4 bit answer
-               if (ReaderReceive(receivedAnswer))
-               {
-                       if ( (parameter != 0) && (memcmp(nt, nt_noattack, 4) == 0) ) continue;
+               // Transmit reader nonce with fake par
+               ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par);

 
 

-                       isNULL = !(nt_attacked[0] == 0) && (nt_attacked[1] == 0) && (nt_attacked[2] == 0) && (nt_attacked[3] == 0);
-                       if ( (isNULL != 0 ) && (memcmp(nt, nt_attacked, 4) != 0) ) continue;
+               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) {
+                               nt_attacked = nt;
+                       }
+                       else {
+                               if (nt_distance == -99999) { // invalid nonce received, try again
+                                       continue;
+                               }
+                               sync_cycles = (sync_cycles - nt_distance);
+//                             Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
+                               continue;
+                       }
+               }

 
 

+               if ((nt != nt_attacked) && nt_attacked) {       // we somehow lost sync. Try to catch up again...
+                       catch_up_cycles = -dist_nt(nt_attacked, nt);
+                       if (catch_up_cycles == 99999) {                 // invalid nonce received. Don't resync on that one.
+                               catch_up_cycles = 0;
+                               continue;
+                       }
+                       if (catch_up_cycles == last_catch_up) {
+                               consecutive_resyncs++;
+                       }
+                       else {
+                               last_catch_up = catch_up_cycles;
+                           consecutive_resyncs = 0;
+                       }
+                       if (consecutive_resyncs < 3) {
+                               Dbprintf("Lost sync in cycle %d. nt_distance=%d. Consecutive Resyncs = %d. Trying one time catch up...\n", i, -catch_up_cycles, consecutive_resyncs);
+                       }
+                       else {  
+                               sync_cycles = sync_cycles + catch_up_cycles;
+                               Dbprintf("Lost sync in cycle %d for the fourth time consecutively (nt_distance = %d). Adjusting sync_cycles to %d.\n", i, -catch_up_cycles, sync_cycles);
+                       }
+                       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))
+               {
+                       catch_up_cycles = 8;    // the PRNG doesn't run during data transfers. 4 Bit = 8 cycles
+       

                        if (nt_diff == 0)
                        {
                        if (nt_diff == 0)
                        {

-                               LED_A_ON();
-                               memcpy(nt_attacked, nt, 4);
-                               //par_mask = 0xf8;
-                               par_low = par & 0x07;
+                               par_low = par & 0x07; // 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();
                        }
 
                        led_on = !led_on;
                        if(led_on) LED_B_ON(); else LED_B_OFF();

+

                        par_list[nt_diff] = par;
                        ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
 
                        par_list[nt_diff] = par;
                        ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
 


@@ -1941,10 +2038,10 @@ void ReaderMifare(uint32_t parameter)
                        }
 
                        nt_diff = (nt_diff + 1) & 0x07;
                        }
 
                        nt_diff = (nt_diff + 1) & 0x07;

-                       mf_nr_ar[3] = nt_diff << 5;
+                       mf_nr_ar[3] = (mf_nr_ar[3] & 0x1F) | (nt_diff << 5);

                        par = par_low;
                } else {
                        par = par_low;
                } else {

-                       if (nt_diff == 0)
+                       if (nt_diff == 0 && first_try)

                        {
                                par++;
                        } else {
                        {
                                par++;
                        } else {


@@ -1953,31 +2050,27 @@ void ReaderMifare(uint32_t parameter)
                }
        }
 
                }
        }
 

-       LogTrace(nt, 4, 0, GetParity(nt, 4), TRUE);
+       LogTrace((const uint8_t *)&nt, 4, 0, GetParity((const uint8_t *)&nt, 4), TRUE);

        LogTrace(par_list, 8, 0, GetParity(par_list, 8), TRUE);
        LogTrace(ks_list, 8, 0, GetParity(ks_list, 8), TRUE);
 
        LogTrace(par_list, 8, 0, GetParity(par_list, 8), TRUE);
        LogTrace(ks_list, 8, 0, GetParity(ks_list, 8), TRUE);
 

-  byte_t buf[48];
-//     UsbCommand ack = {CMD_ACK, {isOK, 0, 0}};
+       mf_nr_ar[3] &= 0x1F;
+       
+       byte_t buf[28];

        memcpy(buf + 0,  uid, 4);
        memcpy(buf + 0,  uid, 4);

-       memcpy(buf + 4,  nt, 4);
+       num_to_bytes(nt, 4, buf + 4);

        memcpy(buf + 8,  par_list, 8);
        memcpy(buf + 16, ks_list, 8);
        memcpy(buf + 8,  par_list, 8);
        memcpy(buf + 16, ks_list, 8);

+       memcpy(buf + 24, mf_nr_ar, 4);

                
                

-       LED_B_ON();
-  cmd_send(CMD_ACK,isOK,0,0,buf,48);
-//     UsbSendPacket((uint8_t *)&ack, sizeof(UsbCommand));
-       LED_B_OFF();    
+       cmd_send(CMD_ACK,isOK,0,0,buf,28);

 
        // Thats it...
        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
        LEDsoff();
        tracing = TRUE;
 
        // Thats it...
        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
        LEDsoff();
        tracing = TRUE;

-       
-       if (MF_DBGLEVEL >= 1)   DbpString("COMMAND mifare FINISHED");

 }
 
 }
 

-

 //-----------------------------------------------------------------------------
 // MIFARE 1K simulate. 
 // 
 //-----------------------------------------------------------------------------
 // MIFARE 1K simulate. 
 // 


@@ -2554,4 +2647,4 @@ done:
        
        Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.byteCnt=%x Uart.byteCntMax=%x", maxDataLen, Uart.state, Uart.byteCnt, Uart.byteCntMax);
        LEDsoff();
        
        Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.byteCnt=%x Uart.byteCntMax=%x", maxDataLen, Uart.state, Uart.byteCnt, Uart.byteCntMax);
        LEDsoff();

-}
\ No newline at end of file
+}