//-----------------------------------------------------------------------------
//
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Low frequency visa 2000 tag commands
// by iceman
// ASK/Manchester, RF/64, STT, 96 bits (complete)
//-----------------------------------------------------------------------------
#include "cmdlfvisa2000.h"
#define BL0CK1 0x56495332
static int CmdHelp(const char *Cmd);
int usage_lf_visa2k_clone(void) {
PrintAndLogEx(NORMAL, "clone a Visa2000 tag to a T55x7 tag.");
PrintAndLogEx(NORMAL, "Usage: lf visa2000 clone [h] <card ID> <Q5>");
PrintAndLogEx(NORMAL, "Options:");
PrintAndLogEx(NORMAL, " h : This help");
PrintAndLogEx(NORMAL, " <card ID> : Visa2k card ID");
PrintAndLogEx(NORMAL, " <Q5> : specify write to Q5 (t5555 instead of t55x7)");
PrintAndLogEx(NORMAL, "");
PrintAndLogEx(NORMAL, "Examples:");
PrintAndLogEx(NORMAL, " lf visa2000 clone 112233");
return 0;
}
int usage_lf_visa2k_sim(void) {
PrintAndLogEx(NORMAL, "Enables simulation of visa2k card with specified card number.");
PrintAndLogEx(NORMAL, "Simulation runs until the button is pressed or another USB command is issued.");
PrintAndLogEx(NORMAL, "");
PrintAndLogEx(NORMAL, "Usage: lf visa2000 sim [h] <card ID>");
PrintAndLogEx(NORMAL, "Options:");
PrintAndLogEx(NORMAL, " h : This help");
PrintAndLogEx(NORMAL, " <card ID> : Visa2k card ID");
PrintAndLogEx(NORMAL, "");
PrintAndLogEx(NORMAL, "Examples:");
PrintAndLogEx(NORMAL, " lf visa2000 sim 112233");
return 0;
}
static uint8_t visa_chksum(uint32_t id) {
uint8_t sum = 0;
for (uint8_t i = 0; i < 32; i += 4)
sum ^= (id >> i) & 0xF;
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[(id >> 28) & 0xF ] << 7;
par |= par_lut[(id >> 24) & 0xF ] << 6;
par |= par_lut[(id >> 20) & 0xF ] << 5;
par |= par_lut[(id >> 16) & 0xF ] << 4;
par |= par_lut[(id >> 12) & 0xF ] << 3;
par |= par_lut[(id >> 8) & 0xF ] << 2;
par |= par_lut[(id >> 4) & 0xF ] << 1;
par |= par_lut[(id & 0xF) ];
return par;
}
// by iceman
// find Visa2000 preamble in already demoded data
int detectVisa2k(uint8_t *dest, size_t *size) {
if (*size < 96) return -1; //make sure buffer has data
size_t startIdx = 0;
uint8_t preamble[] = {0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0};
if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
return -2; //preamble not found
if (*size != 96) return -3; //wrong demoded size
//return start position
return (int)startIdx;
}
/**
*
* 56495332 00096ebd 00000077 —> tag id 618173
* aaaaaaaa iiiiiiii -----ppc
*
* a = fixed value ascii 'VIS2'
* i = card id
* p = even parity bit for each nibble in card id.
* c = checksum (xor of card id)
*
**/
//see ASKDemod for what args are accepted
int CmdVisa2kDemod(const char *Cmd) {
save_restoreGB(GRAPH_SAVE);
//sCmdAskEdgeDetect("");
//ASK / Manchester
bool st = true;
if (!ASKDemod_ext("64 0 0", false, false, 1, &st)) {
PrintAndLogEx(DEBUG, "DEBUG: Error - Visa2k: ASK/Manchester Demod failed");
save_restoreGB(GRAPH_RESTORE);
return 0;
}
size_t size = DemodBufferLen;
int ans = detectVisa2k(DemodBuffer, &size);
if (ans < 0) {
if (ans == -1)
PrintAndLogEx(DEBUG, "DEBUG: Error - Visa2k: too few bits found");
else if (ans == -2)
PrintAndLogEx(DEBUG, "DEBUG: Error - Visa2k: preamble not found");
else if (ans == -3)
PrintAndLogEx(DEBUG, "DEBUG: Error - Visa2k: Size not correct: %d", size);
else
PrintAndLogEx(DEBUG, "DEBUG: Error - Visa2k: ans: %d", ans);
save_restoreGB(GRAPH_RESTORE);
return 0;
}
setDemodBuff(DemodBuffer, 96, ans);
setClockGrid(g_DemodClock, g_DemodStartIdx + (ans * g_DemodClock));
//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) {
PrintAndLogEx(DEBUG, "DEBUG: error: Visa2000 checksum failed %x - %x\n", chk, calc);
save_restoreGB(GRAPH_RESTORE);
return 0;
}
// parity
uint8_t calc_par = visa_parity(raw2);
uint8_t chk_par = (raw3 & 0xFF0) >> 4;
if (calc_par != chk_par) {
PrintAndLogEx(DEBUG, "DEBUG: error: Visa2000 parity failed %x - %x\n", chk_par, calc_par);
save_restoreGB(GRAPH_RESTORE);
return 0;
}
PrintAndLogEx(SUCCESS, "Visa2000 Tag Found: Card ID %u, Raw: %08X%08X%08X", raw2, raw1, raw2, raw3);
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) {
lf_read(true, 20000);
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};
char cmdp = tolower(param_getchar(Cmd, 0));
if (strlen(Cmd) == 0 || cmdp == 'h') return usage_lf_visa2k_clone();
id = param_get32ex(Cmd, 0, 0, 10);
//Q5
if (param_getchar(Cmd, 1) == 'Q' || param_getchar(Cmd, 1) == 'q')
blocks[0] = T5555_MODULATION_MANCHESTER | T5555_SET_BITRATE(64) | T5555_ST_TERMINATOR | 3 << T5555_MAXBLOCK_SHIFT;
blocks[2] = id;
blocks[3] = (visa_parity(id) << 4) | visa_chksum(id);
PrintAndLogEx(INFO, "Preparing to clone Visa2000 to T55x7 with CardId: %u", id);
print_blocks(blocks, 4);
UsbCommand resp;
UsbCommand c = {CMD_T55XX_WRITE_BLOCK, {0, 0, 0}};
for (uint8_t i = 0; i < 4; i++) {
c.arg[0] = blocks[i];
c.arg[1] = i;
clearCommandBuffer();
SendCommand(&c);
if (!WaitForResponseTimeout(CMD_ACK, &resp, T55XX_WRITE_TIMEOUT)) {
PrintAndLogEx(WARNING, "Error occurred, device did not respond during write operation.");
return -1;
}
}
return 0;
}
int CmdVisa2kSim(const char *Cmd) {
uint32_t id = 0;
char cmdp = param_getchar(Cmd, 0);
if (strlen(Cmd) == 0 || cmdp == 'h' || cmdp == 'H') return usage_lf_visa2k_sim();
id = param_get32ex(Cmd, 0, 0, 10);
uint8_t clk = 64, encoding = 1, separator = 1, invert = 0;
uint16_t arg1, arg2;
size_t size = 96;
arg1 = clk << 8 | encoding;
arg2 = invert << 8 | separator;
PrintAndLogEx(SUCCESS, "Simulating Visa2000 - CardId: %u", id);
UsbCommand c = {CMD_ASK_SIM_TAG, {arg1, arg2, size}};
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);
clearCommandBuffer();
SendCommand(&c);
return 0;
}
static command_t CommandTable[] = {
{"help", CmdHelp, 1, "This help"},
{"demod", CmdVisa2kDemod, 1, "demodulate an VISA2000 tag from the GraphBuffer"},
{"read", CmdVisa2kRead, 0, "attempt to read and extract tag data from the antenna"},
{"clone", CmdVisa2kClone, 0, "clone Visa2000 to t55x7"},
{"sim", CmdVisa2kSim, 0, "simulate Visa2000 tag"},
{NULL, NULL, 0, NULL}
};
int CmdLFVisa2k(const char *Cmd) {
clearCommandBuffer();
CmdsParse(CommandTable, Cmd);
return 0;
}
int CmdHelp(const char *Cmd) {
CmdsHelp(CommandTable);
return 0;
}