Update README.md

[proxmark3-svn] / client / cmdlfvisa2000.c

diff --git a/client/cmdlfvisa2000.c b/client/cmdlfvisa2000.c
index 42e1a00ff88e1519898e38aed5333cca5cd70bae..e828f3749ac5d68dbddc69e5479d6a28c8d788f0 100644 (file)
--- a/client/cmdlfvisa2000.c
+++ b/client/cmdlfvisa2000.c
@@ -45,13 +45,45 @@ static uint8_t visa_chksum( uint32_t id ) {
     return sum & 0xF;
 }
 
+static uint8_t visa_parity( uint32_t id) {
+       // 4bit parity LUT
+       uint8_t par_lut[] = {
+               0,1,1,0
+               ,1,0,0,1
+               ,1,0,0,1
+               ,0,1,1,0
+       };      
+       uint8_t par = 0;
+       par |= par_lut[ NIBBLE_HIGH( (id >> 24) & 0xFF) ] << 7;
+       par |= par_lut[ NIBBLE_LOW( (id >> 24) & 0xFF) ] << 6;
+       par |= par_lut[ NIBBLE_HIGH( (id >> 16) & 0xFF) ] << 5;
+       par |= par_lut[ NIBBLE_LOW( (id >> 16) & 0xFF) ] << 4;
+       par |= par_lut[ NIBBLE_HIGH( (id >> 8) & 0xFF) ] << 3;
+       par |= par_lut[ NIBBLE_LOW( (id >> 8) & 0xFF) ] << 2;
+       par |= par_lut[ NIBBLE_HIGH( id & 0xFF ) ] << 1;
+       par |= par_lut[ NIBBLE_LOW( id & 0xFF) ];
+       return par;     
+}
+
+
+/**
+*
+* 56495332 00096ebd 00000077 —> tag id 618173
+* aaaaaaaa iiiiiiii -----..c
+*
+* a = fixed value  ascii 'VIS2'
+* i = card id
+* c = checksum  (xor of card id)
+* . = unknown 
+* 
+**/
 //see ASKDemod for what args are accepted
 int CmdVisa2kDemod(const char *Cmd) {
 
        // save GraphBuffer - to restore it later       
        save_restoreGB(1);
        
-       CmdAskEdgeDetect("");
+       //sCmdAskEdgeDetect("");
        
        //ASK / Manchester
        bool st = TRUE;
@@ -77,36 +109,47 @@ int CmdVisa2kDemod(const char *Cmd) {
                return 0;
        }
        setDemodBuf(DemodBuffer, 96, ans);
-       
+       setGrid_Clock(64);
+               
        //got a good demod
        uint32_t raw1 = bytebits_to_byte(DemodBuffer, 32);
        uint32_t raw2 = bytebits_to_byte(DemodBuffer+32, 32);
        uint32_t raw3 = bytebits_to_byte(DemodBuffer+64, 32);
-
+       
        // chksum
        uint8_t calc = visa_chksum(raw2);
        uint8_t chk = raw3 & 0xF;       
+               
        // test checksums
        if ( chk != calc ) { 
                printf("DEBUG: error: Visa2000 checksum failed %x - %x\n", chk, calc);
                save_restoreGB(0);
                return 0;
        }
+       // parity
+       uint8_t calc_par = visa_parity(raw2);
+       uint8_t chk_par = (raw3 & 0xFF0) >> 4;
+       if ( calc_par != chk_par) {
+               printf("DEBUG: error: Visa2000 parity failed %x - %x\n", chk_par, calc_par);
+               save_restoreGB(0);
+               return 0;               
+       }
        PrintAndLog("Visa2000 Tag Found: Card ID %u,  Raw: %08X%08X%08X", raw2,  raw1 ,raw2, raw3);
        save_restoreGB(0);
        return 1;
 }
 
+// 64*96*2=12288 samples just in case we just missed the first preamble we can still catch 2 of them
 int CmdVisa2kRead(const char *Cmd) {
        CmdLFRead("s");
-       getSamples("16000",TRUE);
+       getSamples("12500",TRUE);
        return CmdVisa2kDemod(Cmd);
 }
 
 int CmdVisa2kClone(const char *Cmd) {
 
        uint64_t id = 0;
-       uint32_t blocks[4] = {T55x7_MODULATION_MANCHESTER | T55x7_BITRATE_RF_64 | T55x7_ST_TERMINATOR |3<<T55x7_MAXBLOCK_SHIFT, BL0CK1, 0};
+       uint32_t blocks[4] = {T55x7_MODULATION_MANCHESTER | T55x7_BITRATE_RF_64 | T55x7_ST_TERMINATOR | 3 << T55x7_MAXBLOCK_SHIFT, BL0CK1, 0};
 
        char cmdp = param_getchar(Cmd, 0);
        if (strlen(Cmd) == 0 || cmdp == 'h' || cmdp == 'H') return usage_lf_visa2k_clone();
@@ -116,12 +159,12 @@ int CmdVisa2kClone(const char *Cmd) {
        //Q5
        if (param_getchar(Cmd, 1) == 'Q' || param_getchar(Cmd, 1) == 'q') {
                //t5555 (Q5) BITRATE = (RF-2)/2 (iceman)
-               blocks[0] = T5555_MODULATION_MANCHESTER | 64<<T5555_BITRATE_SHIFT | T5555_ST_TERMINATOR | 3<<T5555_MAXBLOCK_SHIFT;
+               blocks[0] = T5555_MODULATION_MANCHESTER | ((64-2)>>1) << T5555_BITRATE_SHIFT | T5555_ST_TERMINATOR | 3 << T5555_MAXBLOCK_SHIFT;
        }
        
        // 
        blocks[2] = id;
-       blocks[3] = visa_chksum(id);
+       blocks[3] =  (visa_parity(id) << 4) | visa_chksum(id);  
 
        PrintAndLog("Preparing to clone Visa2000 to T55x7 with CardId: %u", id);
        PrintAndLog("Blk | Data ");
@@ -163,9 +206,9 @@ int CmdVisa2kSim(const char *Cmd) {
 
        UsbCommand c = {CMD_ASK_SIM_TAG, {arg1, arg2, size}};
 
-       uint32_t blocks[3] = { BL0CK1, id,  visa_chksum(id) };
+       uint32_t blocks[3] = { BL0CK1, id, (visa_parity(id) << 4) | visa_chksum(id) };
 
-       for(int i=0; i<3; ++i)
+       for(int i = 0; i < 3; ++i)
                num_to_bytebits(blocks[i], 32, c.d.asBytes + i*32);
 
        clearCommandBuffer();
@@ -175,6 +218,7 @@ int CmdVisa2kSim(const char *Cmd) {
 
 static command_t CommandTable[] = {
     {"help",   CmdHelp,                1, "This help"},
+       {"demod",       CmdVisa2kDemod, 1, "Attempt to demod from GraphBuffer"},        
        {"read",        CmdVisa2kRead,  0, "Attempt to read and extract tag data"},
        {"clone",       CmdVisa2kClone, 0, "clone Visa2000 tag"},
        {"sim",         CmdVisa2kSim,   0, "simulate Visa2000 tag"},