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FIX: lf visa2000 - identified unknown nibble in checksum. Is not checksum, but the even parity of the last 2bytes in ID.

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This commit is contained in:
iceman1001 2017-03-05 16:56:24 +01:00
parent bdeac4021a
commit fb26bb5436
1 changed files with 28 additions and 2 deletions
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30
client/cmdlfvisa2000.c
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@ -45,6 +45,23 @@ 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 >> 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
@ -98,12 +115,21 @@ int CmdVisa2kDemod(const char *Cmd) {
// 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 & 0xF0) >> 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;
@ -133,7 +159,7 @@ int CmdVisa2kClone(const char *Cmd) {
//
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 ");
@ -175,7 +201,7 @@ 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)
num_to_bytebits(blocks[i], 32, c.d.asBytes + i*32);