proxmark3/client/cmdlfawid.c

//-----------------------------------------------------------------------------
// Authored by Craig Young <cyoung@tripwire.com> based on cmdlfhid.c structure
//
// cmdlfhid.c is Copyright (C) 2010 iZsh <izsh at fail0verflow.com>
//
// 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 AWID26/50 commands
// FSK2a, RF/50, 96 bits (complete)
//-----------------------------------------------------------------------------
#include "cmdlfawid.h"  // AWID function declarations

static int CmdHelp(const char *Cmd);
/*
static int usage_lf_awid_read(void) {
    PrintAndLogEx(NORMAL, "Enables AWID compatible reader mode printing details of scanned AWID26 or AWID50 tags.");
    PrintAndLogEx(NORMAL, "By default, values are printed and logged until the button is pressed or another USB command is issued.");
    PrintAndLogEx(NORMAL, "If the [1] option is provided, reader mode is exited after reading a single AWID card.");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Usage:  lf awid read [h] [1]");
    PrintAndLogEx(NORMAL, "Options:");
    PrintAndLogEx(NORMAL, "      h :  This help");
    PrintAndLogEx(NORMAL, "      1 : (optional) stop after reading a single card");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Examples:");
    PrintAndLogEx(NORMAL, "       lf awid read");
    PrintAndLogEx(NORMAL, "       lf awid read 1");
    return 0;
}
*/
static int usage_lf_awid_sim(void) {
    PrintAndLogEx(NORMAL, "Enables simulation of AWID card with specified facility-code and card number.");
    PrintAndLogEx(NORMAL, "Simulation runs until the button is pressed or another USB command is issued.");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Usage:  lf awid sim [h] <format> <facility-code> <card-number>");
    PrintAndLogEx(NORMAL, "Options:");
    PrintAndLogEx(NORMAL, "                h :  This help");
    PrintAndLogEx(NORMAL, "         <format> :  format length 26|34|37|50");
    PrintAndLogEx(NORMAL, "  <facility-code> :  8|16bit value facility code");
    PrintAndLogEx(NORMAL, "    <card number> :  16|32-bit value card number");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Examples:");
    PrintAndLogEx(NORMAL, "       lf awid sim 26 224 1337");
    PrintAndLogEx(NORMAL, "       lf awid sim 50 2001 deadc0de");
    return 0;
}

static int usage_lf_awid_clone(void) {
    PrintAndLogEx(NORMAL, "Enables cloning of AWID card with specified facility-code and card number onto T55x7.");
    PrintAndLogEx(NORMAL, "The T55x7 must be on the antenna when issuing this command.  T55x7 blocks are calculated and printed in the process.");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Usage:  lf awid clone [h] <format> <facility-code> <card-number> [Q5]");
    PrintAndLogEx(NORMAL, "Options:");
    PrintAndLogEx(NORMAL, "                h :  This help");
    PrintAndLogEx(NORMAL, "         <format> :  format length 26|34|37|50");
    PrintAndLogEx(NORMAL, "  <facility-code> :  8|16bit value facility code");
    PrintAndLogEx(NORMAL, "    <card number> :  16|32-bit value card number");
    PrintAndLogEx(NORMAL, "               Q5 :  optional - clone to Q5 (T5555) instead of T55x7 chip");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Examples:");
    PrintAndLogEx(NORMAL, "       lf awid clone 26 224 1337");
    PrintAndLogEx(NORMAL, "       lf awid clone 50 2001 13371337");
    return 0;
}

static int usage_lf_awid_brute(void) {
    PrintAndLogEx(NORMAL, "Enables bruteforce of AWID reader with specified facility-code.");
    PrintAndLogEx(NORMAL, "This is a attack against reader. if cardnumber is given, it starts with it and goes up / down one step");
    PrintAndLogEx(NORMAL, "if cardnumber is not given, it starts with 1 and goes up to 65535");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Usage:  lf awid brute [h] [v] a <format> f <facility-code> c <cardnumber> d <delay>");
    PrintAndLogEx(NORMAL, "Options:");
    PrintAndLogEx(NORMAL, "       h                 :  This help");
    PrintAndLogEx(NORMAL, "       a <format>        :  format length 26|50");
    PrintAndLogEx(NORMAL, "       f <facility-code> :  8|16bit value facility code");
    PrintAndLogEx(NORMAL, "       c <cardnumber>    :  (optional) cardnumber to start with, max 65535");
    PrintAndLogEx(NORMAL, "       d <delay>         :  delay betweens attempts in ms. Default 1000ms");
    PrintAndLogEx(NORMAL, "       v                 :  verbose logging, show all tries");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Examples:");
    PrintAndLogEx(NORMAL, "       lf awid brute a 26 f 224");
    PrintAndLogEx(NORMAL, "       lf awid brute a 50 f 2001 d 2000");
    PrintAndLogEx(NORMAL, "       lf awid brute v a 50 f 2001 c 200 d 2000");
    return 0;
}

static bool sendPing(void) {
    PacketCommandOLD ping = {CMD_PING, {1, 2, 3}, {{0}}};
    SendCommand(&ping);
    SendCommand(&ping);
    SendCommand(&ping);
    clearCommandBuffer();
    PacketResponseNG resp;
    if (!WaitForResponseTimeout(CMD_ACK, &resp, 1000))
        return false;
    return true;
}

static bool sendTry(uint8_t fmtlen, uint32_t fc, uint32_t cn, uint32_t delay, uint8_t *bits, size_t bs_len, bool verbose) {

    if (verbose)
        PrintAndLogEx(INFO, "Trying FC: %u; CN: %u", fc, cn);

    if (!getAWIDBits(fmtlen, fc, cn, bits)) {
        PrintAndLogEx(WARNING, "Error with tag bitstream generation.");
        return false;
    }

    uint8_t clk = 50, high = 10, low = 8, invert = 1;
    uint64_t arg1 = (high << 8) + low;
    uint64_t arg2 = (invert << 8) + clk;

    PacketCommandOLD c = {CMD_FSK_SIM_TAG, {arg1, arg2, bs_len}, {{0}}};
    memcpy(c.d.asBytes, bits, bs_len);
    clearCommandBuffer();
    SendCommand(&c);

    msleep(delay);
    sendPing();
    return true;
}

static void verify_values(uint8_t *fmtlen, uint32_t *fc, uint32_t *cn) {
    switch (*fmtlen) {
        case 50:
            if ((*fc & 0xFFFF) != *fc) {
                *fc &= 0xFFFF;
                PrintAndLogEx(INFO, "Facility-Code Truncated to 16-bits (AWID50): %u", *fc);
            }
            break;
        case 37:
            if ((*fc & 0x1FFF) != *fc) {
                *fc &= 0x1FFF;
                PrintAndLogEx(INFO, "Facility-Code Truncated to 13-bits (AWID37): %u", *fc);
            }
            if ((*cn & 0x3FFFF) != *cn) {
                *cn &= 0x3FFFF;
                PrintAndLogEx(INFO, "Card Number Truncated to 18-bits (AWID37): %u", *cn);
            }
            break;
        case 34:
            if ((*fc & 0xFF) != *fc) {
                *fc &= 0xFF;
                PrintAndLogEx(INFO, "Facility-Code Truncated to 8-bits (AWID34): %u", *fc);
            }
            if ((*cn & 0xFFFFFF) != *cn) {
                *cn &= 0xFFFFFF;
                PrintAndLogEx(INFO, "Card Number Truncated to 24-bits (AWID34): %u", *cn);
            }
            break;
        case 26:
        default:
            *fmtlen = 26;
            if ((*fc & 0xFF) != *fc) {
                *fc &= 0xFF;
                PrintAndLogEx(INFO, "Facility-Code Truncated to 8-bits (AWID26): %u", *fc);
            }
            if ((*cn & 0xFFFF) != *cn) {
                *cn &= 0xFFFF;
                PrintAndLogEx(INFO, "Card Number Truncated to 16-bits (AWID26): %u", *cn);
            }
            break;
    }
}
/*
// this read loops on device side.
// uses the demod in lfops.c
static int CmdAWIDRead_device(const char *Cmd) {

    if (Cmd[0] == 'h' || Cmd[0] == 'H') return usage_lf_awid_read();
    uint8_t findone = (Cmd[0] == '1') ? 1 : 0;
    PacketCommandOLD c = {CMD_AWID_DEMOD_FSK, {findone, 0, 0}, {{0}}};
    clearCommandBuffer();
    SendCommand(&c);
    return 0;
}
*/
//by marshmellow
//AWID Prox demod - FSK2a RF/50 with preamble of 00000001  (always a 96 bit data stream)
//print full AWID Prox ID and some bit format details if found
static int CmdAWIDDemod(const char *Cmd) {
    (void)Cmd; // Cmd is not used so far
    uint8_t bits[MAX_GRAPH_TRACE_LEN] = {0};
    size_t size = getFromGraphBuf(bits);
    if (size == 0) {
        PrintAndLogEx(DEBUG, "DEBUG: Error - AWID not enough samples");
        return 0;
    }
    //get binary from fsk wave
    int waveIdx = 0;
    int idx = detectAWID(bits, &size, &waveIdx);
    if (idx <= 0) {

        if (idx == -1)
            PrintAndLogEx(DEBUG, "DEBUG: Error - AWID not enough samples");
        else if (idx == -2)
            PrintAndLogEx(DEBUG, "DEBUG: Error - AWID only noise found");
        else if (idx == -3)
            PrintAndLogEx(DEBUG, "DEBUG: Error - AWID problem during FSK demod");
        else if (idx == -4)
            PrintAndLogEx(DEBUG, "DEBUG: Error - AWID preamble not found");
        else if (idx == -5)
            PrintAndLogEx(DEBUG, "DEBUG: Error - AWID size not correct, size %d", size);
        else
            PrintAndLogEx(DEBUG, "DEBUG: Error - AWID error demoding fsk %d", idx);

        return 0;
    }

    setDemodBuff(bits, size, idx);
    setClockGrid(50, waveIdx + (idx * 50));


    // Index map
    // 0            10            20            30              40            50              60
    // |            |             |             |               |             |               |
    // 01234567 890 1 234 5 678 9 012 3 456 7 890 1 234 5 678 9 012 3 456 7 890 1 234 5 678 9 012 3 - to 96
    // -----------------------------------------------------------------------------
    // 00000001 000 1 110 1 101 1 011 1 101 1 010 0 000 1 000 1 010 0 001 0 110 1 100 0 000 1 000 1
    // premable bbb o bbb o bbw o fff o fff o ffc o ccc o ccc o ccc o ccc o ccc o wxx o xxx o xxx o - to 96
    //          |---26 bit---|    |-----117----||-------------142-------------|
    // b = format bit len, o = odd parity of last 3 bits
    // f = facility code, c = card number
    // w = wiegand parity
    // (26 bit format shown)

    //get raw ID before removing parities
    uint32_t rawLo = bytebits_to_byte(bits + idx + 64, 32);
    uint32_t rawHi = bytebits_to_byte(bits + idx + 32, 32);
    uint32_t rawHi2 = bytebits_to_byte(bits + idx, 32);

    size = removeParity(bits, idx + 8, 4, 1, 88);
    if (size != 66) {
        PrintAndLogEx(DEBUG, "DEBUG: Error - AWID at parity check-tag size does not match AWID format");
        return 0;
    }
    // ok valid card found!

    // Index map
    // 0           10         20        30          40        50        60
    // |           |          |         |           |         |         |
    // 01234567 8 90123456 7890123456789012 3 456789012345678901234567890123456
    // -----------------------------------------------------------------------------
    // 00011010 1 01110101 0000000010001110 1 000000000000000000000000000000000
    // bbbbbbbb w ffffffff cccccccccccccccc w xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
    // |26 bit|   |-117--| |-----142------|
    //
    // 00110010 0 0000111110100000 00000000000100010010100010000111 1 000000000
    // bbbbbbbb w ffffffffffffffff cccccccccccccccccccccccccccccccc w xxxxxxxxx
    // |50 bit|   |----4000------| |-----------2248975------------|
    // b = format bit len, o = odd parity of last 3 bits
    // f = facility code, c = card number
    // w = wiegand parity

    uint32_t fc = 0;
    uint32_t cardnum = 0;
    uint32_t code1 = 0;
    uint32_t code2 = 0;
    uint8_t fmtLen = bytebits_to_byte(bits, 8);

    switch (fmtLen) {
        case 26:
            fc = bytebits_to_byte(bits + 9, 8);
            cardnum = bytebits_to_byte(bits + 17, 16);
            code1 = bytebits_to_byte(bits + 8, fmtLen);
            PrintAndLogEx(SUCCESS, "AWID Found - BitLength: %d, FC: %d, Card: %u - Wiegand: %x, Raw: %08x%08x%08x", fmtLen, fc, cardnum, code1, rawHi2, rawHi, rawLo);
            break;
        case 34:
            fc = bytebits_to_byte(bits + 9, 8);
            cardnum = bytebits_to_byte(bits + 17, 24);
            code1 = bytebits_to_byte(bits + 8, (fmtLen - 32));
            code2 = bytebits_to_byte(bits + 8 + (fmtLen - 32), 32);
            PrintAndLogEx(SUCCESS, "AWID Found - BitLength: %d, FC: %d, Card: %u - Wiegand: %x%08x, Raw: %08x%08x%08x", fmtLen, fc, cardnum, code1, code2, rawHi2, rawHi, rawLo);
            break;
        case 37:
            fc = bytebits_to_byte(bits + 9, 13);
            cardnum = bytebits_to_byte(bits + 22, 18);
            code1 = bytebits_to_byte(bits + 8, (fmtLen - 32));
            code2 = bytebits_to_byte(bits + 8 + (fmtLen - 32), 32);
            PrintAndLogEx(SUCCESS, "AWID Found - BitLength: %d, FC: %d, Card: %u - Wiegand: %x%08x, Raw: %08x%08x%08x", fmtLen, fc, cardnum, code1, code2, rawHi2, rawHi, rawLo);
            break;
        // case 40:
        // break;
        case 50:
            fc = bytebits_to_byte(bits + 9, 16);
            cardnum = bytebits_to_byte(bits + 25, 32);
            code1 = bytebits_to_byte(bits + 8, (fmtLen - 32));
            code2 = bytebits_to_byte(bits + 8 + (fmtLen - 32), 32);
            PrintAndLogEx(SUCCESS, "AWID Found - BitLength: %d, FC: %d, Card: %u - Wiegand: %x%08x, Raw: %08x%08x%08x", fmtLen, fc, cardnum, code1, code2, rawHi2, rawHi, rawLo);
            break;
        default:
            if (fmtLen > 32) {
                cardnum = bytebits_to_byte(bits + 8 + (fmtLen - 17), 16);
                code1 = bytebits_to_byte(bits + 8, fmtLen - 32);
                code2 = bytebits_to_byte(bits + 8 + (fmtLen - 32), 32);
                PrintAndLogEx(SUCCESS, "AWID Found - BitLength: %d -unknown BitLength- (%u) - Wiegand: %x%08x, Raw: %08x%08x%08x", fmtLen, cardnum, code1, code2, rawHi2, rawHi, rawLo);
            } else {
                cardnum = bytebits_to_byte(bits + 8 + (fmtLen - 17), 16);
                code1 = bytebits_to_byte(bits + 8, fmtLen);
                PrintAndLogEx(SUCCESS, "AWID Found - BitLength: %d -unknown BitLength- (%u) - Wiegand: %x, Raw: %08x%08x%08x", fmtLen, cardnum, code1, rawHi2, rawHi, rawLo);
            }
            break;
    }

    PrintAndLogEx(DEBUG, "DEBUG: AWID idx: %d, Len: %d Printing Demod Buffer:", idx, size);
    if (g_debugMode)
        printDemodBuff();

    return 1;
}

// this read is the "normal" read,  which download lf signal and tries to demod here.
static int CmdAWIDRead(const char *Cmd) {
    lf_read(true, 12000);
    return CmdAWIDDemod(Cmd);
}

static int CmdAWIDSim(const char *Cmd) {
    uint32_t fc = 0, cn = 0;
    uint8_t fmtlen = 0;
    uint8_t bits[96];
    size_t size = sizeof(bits);
    memset(bits, 0x00, size);

    char cmdp = param_getchar(Cmd, 0);
    if (strlen(Cmd) == 0 || cmdp == 'h' || cmdp == 'H') return usage_lf_awid_sim();

    fmtlen = param_get8(Cmd, 0);
    fc = param_get32ex(Cmd, 1, 0, 10);
    cn = param_get32ex(Cmd, 2, 0, 10);
    if (!fc || !cn) return usage_lf_awid_sim();

    verify_values(&fmtlen, &fc, &cn);

    PrintAndLogEx(SUCCESS, "Simulating AWID %u -- FC: %u; CN: %u\n", fmtlen, fc, cn);
    PrintAndLogEx(SUCCESS, "Press pm3-button to abort simulation or run another command");

    if (!getAWIDBits(fmtlen, fc, cn, bits)) {
        PrintAndLogEx(WARNING, "Error with tag bitstream generation.");
        return 1;
    }

    uint8_t clk = 50, high = 10, low = 8, invert = 1;
    uint64_t arg1 = (high << 8) + low;
    uint64_t arg2 = (invert << 8) + clk;

    // AWID uses: FSK2a fcHigh: 10, fcLow: 8, clk: 50, invert: 1
    // arg1 --- fcHigh<<8 + fcLow
    // arg2 --- Inversion and clk setting
    // 96   --- Bitstream length: 96-bits == 12 bytes
    PacketCommandOLD c = {CMD_FSK_SIM_TAG, {arg1, arg2, size}, {{0}}};
    memcpy(c.d.asBytes, bits, size);
    clearCommandBuffer();
    SendCommand(&c);
    return 0;
}

static int CmdAWIDClone(const char *Cmd) {
    uint32_t blocks[4] = {T55x7_MODULATION_FSK2a | T55x7_BITRATE_RF_50 | 3 << T55x7_MAXBLOCK_SHIFT, 0, 0, 0};
    uint32_t fc = 0, cn = 0;
    uint8_t fmtlen = 0;
    uint8_t bits[96];
    uint8_t *bs = bits;
    memset(bs, 0, sizeof(bits));

    char cmdp = tolower(param_getchar(Cmd, 0));
    if (strlen(Cmd) == 0 || cmdp == 'h') return usage_lf_awid_clone();

    fmtlen = param_get8(Cmd, 0);
    fc = param_get32ex(Cmd, 1, 0, 10);
    cn = param_get32ex(Cmd, 2, 0, 10);

    if (!fc || !cn) return usage_lf_awid_clone();

    if (tolower(param_getchar(Cmd, 3)) == 'q')
        //t5555 (Q5) BITRATE = (RF-2)/2 (iceman)
        blocks[0] = T5555_MODULATION_FSK2 | T5555_INVERT_OUTPUT | T5555_SET_BITRATE(50) | 3 << T5555_MAXBLOCK_SHIFT;

    verify_values(&fmtlen, &fc, &cn);

    if (!getAWIDBits(fmtlen, fc, cn, bs)) {
        PrintAndLogEx(WARNING, "Error with tag bitstream generation.");
        return 1;
    }

    blocks[1] = bytebits_to_byte(bs, 32);
    blocks[2] = bytebits_to_byte(bs + 32, 32);
    blocks[3] = bytebits_to_byte(bs + 64, 32);

    PrintAndLogEx(INFO, "Preparing to clone AWID %u to T55x7 with FC: %u, CN: %u", fmtlen, fc, cn);
    print_blocks(blocks, 4);

    PacketResponseNG resp;
    PacketCommandOLD c = {CMD_T55XX_WRITE_BLOCK, {0, 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;
}

static int CmdAWIDBrute(const char *Cmd) {

    bool errors = false, verbose = false;
    uint32_t fc = 0, cn = 0, delay = 1000;
    uint8_t fmtlen = 0;
    uint8_t bits[96];
    size_t size = sizeof(bits);
    memset(bits, 0x00, size);
    uint8_t cmdp = 0;

    while (param_getchar(Cmd, cmdp) != 0x00 && !errors) {
        switch (tolower(param_getchar(Cmd, cmdp))) {
            case 'h':
                return usage_lf_awid_brute();
            case 'f':
                fc =  param_get32ex(Cmd, cmdp + 1, 0, 10);
                if (!fc)
                    errors = true;
                cmdp += 2;
                break;
            case 'd':
                // delay between attemps,  defaults to 1000ms.
                delay = param_get32ex(Cmd, cmdp + 1, 1000, 10);
                cmdp += 2;
                break;
            case 'c':
                cn = param_get32ex(Cmd, cmdp + 1, 0, 10);
                // truncate cardnumber.
                cn &= 0xFFFF;
                cmdp += 2;
                break;
            case 'a':
                fmtlen = param_get8(Cmd, cmdp + 1);
                cmdp += 2;
                break;
            case 'v':
                verbose = true;
                cmdp++;
                break;
            default:
                PrintAndLogEx(WARNING, "Unknown parameter '%c'", param_getchar(Cmd, cmdp));
                errors = true;
                break;
        }
    }
    if (fc == 0) errors = true;
    if (errors) return usage_lf_awid_brute();

    // limit fc according to selected format
    switch (fmtlen) {
        case 50:
            if ((fc & 0xFFFF) != fc) {
                fc &= 0xFFFF;
                PrintAndLogEx(INFO, "Facility-code truncated to 16-bits (AWID50): %u", fc);
            }
            break;
        default:
            if ((fc & 0xFF) != fc) {
                fc &= 0xFF;
                PrintAndLogEx(INFO, "Facility-code truncated to 8-bits (AWID26): %u", fc);
            }
            break;
    }

    PrintAndLogEx(SUCCESS, "Bruteforceing AWID %d Reader", fmtlen);
    PrintAndLogEx(SUCCESS, "Press pm3-button to abort simulation or press key");

    uint16_t up = cn;
    uint16_t down = cn;

    // main loop
    for (;;) {

        if (IsOffline()) {
            PrintAndLogEx(WARNING, "Device offline\n");
            return  2;
        }
        if (ukbhit()) {
            int gc = getchar();
            (void)gc;
            PrintAndLogEx(INFO, "aborted via keyboard!");
            return sendPing();
        }

        // Do one up
        if (up < 0xFFFF)
            if (!sendTry(fmtlen, fc, up++, delay, bits, size, verbose)) return 1;

        // Do one down  (if cardnumber is given)
        if (cn > 1)
            if (down > 1)
                if (!sendTry(fmtlen, fc, --down, delay, bits, size, verbose)) return 1;
    }
    return 0;
}

static command_t CommandTable[] = {
    {"help",    CmdHelp,        1, "this help"},
    {"demod",   CmdAWIDDemod,   0, "demodulate an AWID FSK tag from the GraphBuffer"},
    {"read",    CmdAWIDRead,    0, "attempt to read and extract tag data"},
    {"clone",   CmdAWIDClone,   0, "clone AWID to T55x7"},
    {"sim",     CmdAWIDSim,     0, "simulate AWID tag"},
    {"brute",   CmdAWIDBrute,   0, "Bruteforce card number against reader"},
    {NULL, NULL, 0, NULL}
};

static int CmdHelp(const char *Cmd) {
    (void)Cmd; // Cmd is not used so far
    CmdsHelp(CommandTable);
    return 0;
}

int CmdLFAWID(const char *Cmd) {
    clearCommandBuffer();
    return CmdsParse(CommandTable, Cmd);
}

//refactored by marshmellow
int getAWIDBits(uint8_t fmtlen, uint32_t fc, uint32_t cn, uint8_t *bits) {

    // the return bits, preamble 0000 0001
    bits[7] = 1;

    uint8_t pre[66];
    memset(pre, 0, sizeof(pre));

    // add formatlength
    num_to_bytebits(fmtlen, 8, pre);

    // add facilitycode, cardnumber and wiegand parity bits
    switch (fmtlen) {
        case 26: {
            uint8_t wiegand[24];
            num_to_bytebits(fc, 8, wiegand);
            num_to_bytebits(cn, 16, wiegand + 8);
            wiegand_add_parity(pre + 8, wiegand,  sizeof(wiegand));
            break;
        }
        case 34: {
            uint8_t wiegand[32];
            num_to_bytebits(fc, 8, wiegand);
            num_to_bytebits(cn, 24, wiegand + 8);
            wiegand_add_parity(pre + 8, wiegand,  sizeof(wiegand));
            break;
        }
        case 37: {
            uint8_t wiegand[31];
            num_to_bytebits(fc, 13, wiegand);
            num_to_bytebits(cn, 18, wiegand + 13);
            wiegand_add_parity(pre + 8, wiegand,  sizeof(wiegand));
            break;
        }
        case 50: {
            uint8_t wiegand[48];
            num_to_bytebits(fc, 16, wiegand);
            num_to_bytebits(cn, 32, wiegand + 16);
            wiegand_add_parity(pre + 8, wiegand, sizeof(wiegand));
            break;
        }
    }

    // add AWID 4bit parity
    size_t bitLen = addParity(pre, bits + 8, 66, 4, 1);

    if (bitLen != 88) return 0;

    PrintAndLogEx(SUCCESS, "awid raw bits:\n %s \n", sprint_bin(bits, bitLen));

    return 1;
}

int demodAWID(void) {
    return CmdAWIDDemod("");
}