hashcracker 0.1.0

struct Config {
    target_hash: array<u32, 8>,
    password_len: u32,
    num_passwords: u32,
    found_flag: atomic<u32>,
    found_password: array<u32, 4>,
    mask: array<u32, 16>,
    mask_len: u32,
    target_hash_extra: array<u32, 8>,
    salt: array<u32, 16>,
    salt_len: u32,
    range_start: u32,
    range_end: u32,
    num_targets: u32,
}

struct Progress {
    count: atomic<u32>,
}
struct TargetEntry {
    hash: array<u32, 8>,
    hash_extra: array<u32, 8>,
}

@group(0) @binding(0) var<storage, read_write> config: Config;
@group(0) @binding(1) var<storage, read_write> progress: Progress;
@group(0) @binding(2) var<storage, read> targets: array<TargetEntry>;

const CHARSET_SIZE: u32 = 62u;
const ROUNDS: u32 = 5000u;

fn rotr64(x: u64, n: u32) -> u64 { return (x >> n) | (x << (64u - n)); }
fn shr64(x: u64, n: u32) -> u64 { return x >> n; }
fn ch_512(x: u64, y: u64, z: u64) -> u64 { return (x & y) ^ ((~x) & z); }
fn maj_512(x: u64, y: u64, z: u64) -> u64 { return (x & y) ^ (x & z) ^ (y & z); }
fn sig0_512(x: u64) -> u64 { return rotr64(x, 28u) ^ rotr64(x, 34u) ^ rotr64(x, 39u); }
fn sig1_512(x: u64) -> u64 { return rotr64(x, 14u) ^ rotr64(x, 18u) ^ rotr64(x, 41u); }
fn gam0_512(x: u64) -> u64 { return rotr64(x, 1u) ^ rotr64(x, 8u) ^ shr64(x, 7u); }
fn gam1_512(x: u64) -> u64 { return rotr64(x, 19u) ^ rotr64(x, 61u) ^ shr64(x, 6u); }

const KH: array<u32, 80> = array<u32, 80>(
    0x428a2f98u, 0x71374491u, 0xb5c0fbcfu, 0xe9b5dba5u,
    0x3956c25bu, 0x59f111f1u, 0x923f82a4u, 0xab1c5ed5u,
    0xd807aa98u, 0x12835b01u, 0x243185beu, 0x550c7dc3u,
    0x72be5d74u, 0x80deb1feu, 0x9bdc06a7u, 0xc19bf174u,
    0xe49b69c1u, 0xefbe4786u, 0x0fc19dc6u, 0x240ca1ccu,
    0x2de92c6fu, 0x4a7484aau, 0x5cb0a9dcu, 0x76f988dau,
    0x983e5152u, 0xa831c66du, 0xb00327c8u, 0xbf597fc7u,
    0xc6e00bf3u, 0xd5a79147u, 0x06ca6351u, 0x14292967u,
    0x27b70a85u, 0x2e1b2138u, 0x4d2c6dfcu, 0x53380d13u,
    0x650a7354u, 0x766a0abbu, 0x81c2c92eu, 0x92722c85u,
    0xa2bfe8a1u, 0xa81a664bu, 0xc24b8b70u, 0xc76c51a3u,
    0xd192e819u, 0xd6990624u, 0xf40e3585u, 0x106aa070u,
    0x19a4c116u, 0x1e376c08u, 0x2748774cu, 0x34b0bcb5u,
    0x391c0cb3u, 0x4ed8aa4au, 0x5b9cca4fu, 0x682e6ff3u,
    0x748f82eeu, 0x78a5636fu, 0x84c87814u, 0x8cc70208u,
    0x90befffau, 0xa4506cebu, 0xbef9a3f7u, 0xc67178f2u,
    0xca273eceu, 0xd186b8c7u, 0xeada7dd6u, 0xf57d4f7fu,
    0x06f067aau, 0x0a637dc5u, 0x113f9804u, 0x1b710b35u,
    0x28db77f5u, 0x32caab7bu, 0x3c9ebe0au, 0x431d67c4u,
    0x4cc5d4beu, 0x597f299cu, 0x5fcb6fabu, 0x6c44198cu,
);

const KL: array<u32, 80> = array<u32, 80>(
    0xd728ae22u, 0x23ef65cdu, 0xec4d3b2fu, 0x8189dbbcu,
    0xf348b538u, 0xb605d019u, 0xaf194f9bu, 0xda6d8118u,
    0xa3030242u, 0x45706fbeu, 0x4ee4b28cu, 0xd5ffb4e2u,
    0xf27b896fu, 0x3b1696b1u, 0x25c71235u, 0xcf692694u,
    0x9ef14ad2u, 0x384f25e3u, 0x8b8cd5b5u, 0x77ac9c65u,
    0x592b0275u, 0x6ea6e483u, 0xbd41fbd4u, 0x831153b5u,
    0xee66dfabu, 0x2db43210u, 0x98fb213fu, 0xbeef0ee4u,
    0x3da88fc2u, 0x930aa725u, 0xe003826fu, 0x0a0e6e70u,
    0x46d22ffcu, 0x5c26c926u, 0x5ac42aedu, 0x9d95b3dfu,
    0x8baf63deu, 0x3c77b2a8u, 0x47edaee6u, 0x1482353bu,
    0x4cf10364u, 0xbc423001u, 0xd0f89791u, 0x0654be30u,
    0xd6ef5218u, 0x5565a910u, 0x5771202au, 0x32bbd1b8u,
    0xb8d2d0c8u, 0x5141ab53u, 0xdf8eeb99u, 0xe19b48a8u,
    0xc5c95a63u, 0xe3418acbu, 0x7763e373u, 0xd6b2b8a3u,
    0x5defb2fcu, 0x43172f60u, 0xa1f0ab72u, 0x1a6439ecu,
    0x23631e28u, 0xde82bde9u, 0xb2c67915u, 0xe372532bu,
    0xea26619cu, 0x21c0c207u, 0xcde0eb1eu, 0xee6ed178u,
    0x72176fbau, 0xa2c898a6u, 0xbef90daeu, 0x131c471bu,
    0x23047d84u, 0x40c72493u, 0x15c9bebcu, 0x9c100d4cu,
    0xcb3e42b6u, 0xfc657e2au, 0x3ad6faecu, 0x4a475817u,
);

fn sha512_block(state: ptr<function, array<u64, 8>>, block: array<u64, 16>) {
    var w: array<u64, 80>;
    for (var i = 0u; i < 16u; i++) { w[i] = block[i]; }
    for (var i = 16u; i < 80u; i++) {
        w[i] = gam1_512(w[i - 2u]) + w[i - 7u] + gam0_512(w[i - 15u]) + w[i - 16u];
    }
    var a = (*state)[0u]; var b = (*state)[1u]; var c = (*state)[2u]; var d = (*state)[3u];
    var e = (*state)[4u]; var f = (*state)[5u]; var g = (*state)[6u]; var h = (*state)[7u];
    for (var i = 0u; i < 80u; i++) {
        let k = (u64(KH[i]) << 32u) | u64(KL[i]);
        let t1 = h + sig1_512(e) + ch_512(e, f, g) + k + w[i];
        let t2 = sig0_512(a) + maj_512(a, b, c);
        h = g; g = f; f = e; e = d + t1; d = c; c = b; b = a; a = t1 + t2;
    }
    (*state)[0u] += a; (*state)[1u] += b; (*state)[2u] += c; (*state)[3u] += d;
    (*state)[4u] += e; (*state)[5u] += f; (*state)[6u] += g; (*state)[7u] += h;
}

fn set_byte_be(buf: ptr<function, array<u32, 16>>, pos: u32, val: u32) {
    let w = pos / 4u;
    let s = (3u - (pos % 4u)) * 8u;
    (*buf)[w] |= (val & 0xFFu) << s;
}

fn set_byte_be64(buf: ptr<function, array<u32, 64>>, pos: u32, val: u32) {
    let w = pos / 4u;
    let s = (3u - (pos % 4u)) * 8u;
    (*buf)[w] |= (val & 0xFFu) << s;
}

fn get_byte(data: array<u32, 64>, pos: u32) -> u32 {
    return (data[pos / 4u] >> ((3u - (pos % 4u)) * 8u)) & 0xFFu;
}

fn sha512_bytes(data: array<u32, 64>, len: u32) -> array<u64, 8> {
    var state: array<u64, 8>;
    let siv_hi = array<u32, 8>(0x6a09e667u, 0xbb67ae85u, 0x3c6ef372u, 0xa54ff53au, 0x510e527fu, 0x9b05688cu, 0x1f83d9abu, 0x5be0cd19u);
    let siv_lo = array<u32, 8>(0xf3bcc908u, 0x84caa73bu, 0xfe94f82bu, 0x5f1d36f1u, 0xade682d1u, 0x2b3e6c1fu, 0xfb41bd6bu, 0x137e2179u);
    for (var i = 0u; i < 8u; i++) {
        state[i] = (u64(siv_hi[i]) << 32u) | u64(siv_lo[i]);
    }

    var offset = 0u;
    while (offset + 128u <= len) {
        var block: array<u64, 16>;
        for (var j = 0u; j < 16u; j++) {
            let boff = offset + j * 8u;
            block[j] = (u64(get_byte(data, boff + 0u)) << 56u)
                     | (u64(get_byte(data, boff + 1u)) << 48u)
                     | (u64(get_byte(data, boff + 2u)) << 40u)
                     | (u64(get_byte(data, boff + 3u)) << 32u)
                     | (u64(get_byte(data, boff + 4u)) << 24u)
                     | (u64(get_byte(data, boff + 5u)) << 16u)
                     | (u64(get_byte(data, boff + 6u)) << 8u)
                     | u64(get_byte(data, boff + 7u));
        }
        sha512_block(&state, block);
        offset += 128u;
    }

    var block: array<u64, 16>;
    for (var j = 0u; j < 16u; j++) { block[j] = u64(0u); }

    let remaining = len - offset;
    for (var i = 0u; i < remaining; i++) {
        let byte_val = get_byte(data, offset + i);
        let word_idx = i / 8u;
        let shift = (7u - (i % 8u)) * 8u;
        block[word_idx] |= u64(byte_val) << shift;
    }

    {
        let pad_pos = remaining;
        let word_idx = pad_pos / 8u;
        let shift = (7u - (pad_pos % 8u)) * 8u;
        block[word_idx] |= u64(0x80u) << shift;
    }

    if (remaining >= 112u) {
        sha512_block(&state, block);
        for (var j = 0u; j < 16u; j++) { block[j] = u64(0u); }
    }

    let bit_len = u64(len) * u64(8u);
    block[14u] = u64(0u);
    block[15u] = bit_len;
    sha512_block(&state, block);
    return state;
}

fn sha512_repeated_seq(seq: array<u32, 4>, seq_len: u32, count: u32) -> array<u64, 8> {
    var state: array<u64, 8>;
    let siv_hi = array<u32, 8>(0x6a09e667u, 0xbb67ae85u, 0x3c6ef372u, 0xa54ff53au, 0x510e527fu, 0x9b05688cu, 0x1f83d9abu, 0x5be0cd19u);
    let siv_lo = array<u32, 8>(0xf3bcc908u, 0x84caa73bu, 0xfe94f82bu, 0x5f1d36f1u, 0xade682d1u, 0x2b3e6c1fu, 0xfb41bd6bu, 0x137e2179u);
    for (var i = 0u; i < 8u; i++) { state[i] = (u64(siv_hi[i]) << 32u) | u64(siv_lo[i]); }

    var total_len = seq_len * count;
    let copies_per_block = 128u / seq_len;

    var full_block: array<u64, 16>;
    for (var i = 0u; i < 16u; i++) { full_block[i] = u64(0u); }
    for (var c = 0u; c < copies_per_block; c++) {
        for (var j = 0u; j < seq_len; j++) {
            let byte_val = seq[seq_len - 1u - j] & 0xFFu;
            let dst_byte = c * seq_len + j;
            let word_idx = dst_byte / 8u;
            let shift = (7u - (dst_byte % 8u)) * 8u;
            full_block[word_idx] |= u64(byte_val) << shift;
        }
    }

    var remaining = count;
    while (remaining >= copies_per_block) {
        sha512_block(&state, full_block);
        remaining -= copies_per_block;
    }

    if (remaining > 0u) {
        var block: array<u64, 16>;
        for (var i = 0u; i < 16u; i++) { block[i] = u64(0u); }
        for (var c = 0u; c < remaining; c++) {
            for (var j = 0u; j < seq_len; j++) {
                let byte_val = seq[seq_len - 1u - j] & 0xFFu;
                let dst_byte = c * seq_len + j;
                let word_idx = dst_byte / 8u;
                let shift = (7u - (dst_byte % 8u)) * 8u;
                block[word_idx] |= u64(byte_val) << shift;
            }
        }

        let pad_pos = remaining * seq_len;
        {
            let word_idx = pad_pos / 8u;
            let shift = (7u - (pad_pos % 8u)) * 8u;
            block[word_idx] |= u64(0x80u) << shift;
        }

        if (pad_pos >= 112u) {
            sha512_block(&state, block);
            for (var i = 0u; i < 16u; i++) { block[i] = u64(0u); }
        }

        let bit_len = u64(total_len) * u64(8u);
        block[14u] = u64(0u);
        block[15u] = bit_len;
        sha512_block(&state, block);
    } else {
        var block: array<u64, 16>;
        for (var i = 0u; i < 16u; i++) { block[i] = u64(0u); }
        {
            let word_idx = 0u;
            let shift = (7u - 0u) * 8u;
            block[word_idx] |= u64(0x80u) << shift;
        }
        let bit_len = u64(total_len) * u64(8u);
        block[14u] = u64(0u);
        block[15u] = bit_len;
        sha512_block(&state, block);
    }

    return state;
}

fn sha512_repeated_seq16(seq: array<u32, 16>, seq_len: u32, count: u32) -> array<u64, 8> {
    var state: array<u64, 8>;
    let siv_hi = array<u32, 8>(0x6a09e667u, 0xbb67ae85u, 0x3c6ef372u, 0xa54ff53au, 0x510e527fu, 0x9b05688cu, 0x1f83d9abu, 0x5be0cd19u);
    let siv_lo = array<u32, 8>(0xf3bcc908u, 0x84caa73bu, 0xfe94f82bu, 0x5f1d36f1u, 0xade682d1u, 0x2b3e6c1fu, 0xfb41bd6bu, 0x137e2179u);
    for (var i = 0u; i < 8u; i++) { state[i] = (u64(siv_hi[i]) << 32u) | u64(siv_lo[i]); }

    var total_len = seq_len * count;
    let copies_per_block = 128u / seq_len;

    var full_block: array<u64, 16>;
    for (var i = 0u; i < 16u; i++) { full_block[i] = u64(0u); }
    for (var c = 0u; c < copies_per_block; c++) {
        for (var j = 0u; j < seq_len; j++) {
            let byte_val = seq[seq_len - 1u - j] & 0xFFu;
            let dst_byte = c * seq_len + j;
            let word_idx = dst_byte / 8u;
            let shift = (7u - (dst_byte % 8u)) * 8u;
            full_block[word_idx] |= u64(byte_val) << shift;
        }
    }

    var remaining = count;
    while (remaining >= copies_per_block) {
        sha512_block(&state, full_block);
        remaining -= copies_per_block;
    }

    if (remaining > 0u) {
        var block: array<u64, 16>;
        for (var i = 0u; i < 16u; i++) { block[i] = u64(0u); }
        for (var c = 0u; c < remaining; c++) {
            for (var j = 0u; j < seq_len; j++) {
                let byte_val = seq[seq_len - 1u - j] & 0xFFu;
                let dst_byte = c * seq_len + j;
                let word_idx = dst_byte / 8u;
                let shift = (7u - (dst_byte % 8u)) * 8u;
                block[word_idx] |= u64(byte_val) << shift;
            }
        }

        let pad_pos = remaining * seq_len;
        {
            let word_idx = pad_pos / 8u;
            let shift = (7u - (pad_pos % 8u)) * 8u;
            block[word_idx] |= u64(0x80u) << shift;
        }

        if (pad_pos >= 112u) {
            sha512_block(&state, block);
            for (var i = 0u; i < 16u; i++) { block[i] = u64(0u); }
        }

        let bit_len = u64(total_len) * u64(8u);
        block[14u] = u64(0u);
        block[15u] = bit_len;
        sha512_block(&state, block);
    } else {
        var block: array<u64, 16>;
        for (var i = 0u; i < 16u; i++) { block[i] = u64(0u); }
        {
            let word_idx = 0u;
            let shift = (7u - 0u) * 8u;
            block[word_idx] |= u64(0x80u) << shift;
        }
        let bit_len = u64(total_len) * u64(8u);
        block[14u] = u64(0u);
        block[15u] = bit_len;
        sha512_block(&state, block);
    }

    return state;
}

fn sha512crypt_hash(pwd: array<u32, 4>, pwd_len: u32) -> array<u64, 8> {
    var msg: array<u32, 64>;
    var pos: u32;
    var digest_b: array<u64, 8>;
    var alt_result: array<u64, 8>;
    var temp_result: array<u64, 8>;

    for (var i = 0u; i < 64u; i++) { msg[i] = 0u; }
    pos = 0u;
    for (var i = 0u; i < pwd_len; i++) {
        set_byte_be64(&msg, pos + i, pwd[pwd_len - 1u - i] & 0xFFu);
    }
    pos += pwd_len;
    for (var i = 0u; i < config.salt_len; i++) {
        set_byte_be64(&msg, pos + i, config.salt[config.salt_len - 1u - i] & 0xFFu);
    }
    pos += config.salt_len;
    for (var i = 0u; i < pwd_len; i++) {
        set_byte_be64(&msg, pos + i, pwd[pwd_len - 1u - i] & 0xFFu);
    }
    pos += pwd_len;
    digest_b = sha512_bytes(msg, pos);

    for (var i = 0u; i < 64u; i++) { msg[i] = 0u; }
    pos = 0u;
    for (var i = 0u; i < pwd_len; i++) {
        set_byte_be64(&msg, pos + i, pwd[pwd_len - 1u - i] & 0xFFu);
    }
    pos += pwd_len;
    for (var i = 0u; i < config.salt_len; i++) {
        set_byte_be64(&msg, pos + i, config.salt[config.salt_len - 1u - i] & 0xFFu);
    }
    pos += config.salt_len;

    var n = pwd_len;
    while (n > 64u) {
        for (var i = 0u; i < 8u; i++) {
            set_byte_be64(&msg, pos + i * 8u + 0u, u32((digest_b[i] >> 56u) & u64(0xFFu)));
            set_byte_be64(&msg, pos + i * 8u + 1u, u32((digest_b[i] >> 48u) & u64(0xFFu)));
            set_byte_be64(&msg, pos + i * 8u + 2u, u32((digest_b[i] >> 40u) & u64(0xFFu)));
            set_byte_be64(&msg, pos + i * 8u + 3u, u32((digest_b[i] >> 32u) & u64(0xFFu)));
            set_byte_be64(&msg, pos + i * 8u + 4u, u32((digest_b[i] >> 24u) & u64(0xFFu)));
            set_byte_be64(&msg, pos + i * 8u + 5u, u32((digest_b[i] >> 16u) & u64(0xFFu)));
            set_byte_be64(&msg, pos + i * 8u + 6u, u32((digest_b[i] >> 8u) & u64(0xFFu)));
            set_byte_be64(&msg, pos + i * 8u + 7u, u32(digest_b[i] & u64(0xFFu)));
        }
        pos += 64u;
        n -= 64u;
    }
    for (var i = 0u; i < n; i++) {
        let word_idx = i / 8u;
        let shift = (7u - (i % 8u)) * 8u;
        set_byte_be64(&msg, pos + i, u32((digest_b[word_idx] >> shift) & u64(0xFFu)));
    }
    pos += n;

    n = pwd_len;
    while (n > 0u) {
        if ((n & 1u) != 0u) {
            for (var i = 0u; i < 8u; i++) {
                set_byte_be64(&msg, pos + i * 8u + 0u, u32((digest_b[i] >> 56u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 1u, u32((digest_b[i] >> 48u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 2u, u32((digest_b[i] >> 40u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 3u, u32((digest_b[i] >> 32u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 4u, u32((digest_b[i] >> 24u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 5u, u32((digest_b[i] >> 16u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 6u, u32((digest_b[i] >> 8u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 7u, u32(digest_b[i] & u64(0xFFu)));
            }
            pos += 64u;
        } else {
            for (var i = 0u; i < pwd_len; i++) {
                set_byte_be64(&msg, pos + i, pwd[pwd_len - 1u - i] & 0xFFu);
            }
            pos += pwd_len;
        }
        n >>= 1u;
    }

    alt_result = sha512_bytes(msg, pos);

    temp_result = sha512_repeated_seq(pwd, pwd_len, pwd_len);
    var P: array<u32, 4>;
    for (var i = 0u; i < 4u; i++) { P[i] = 0u; }
    for (var i = 0u; i < pwd_len; i++) {
        let src_idx = i % 64u;
        let word_idx = src_idx / 8u;
        let shift = (7u - (src_idx % 8u)) * 8u;
        let byte_val = u32((temp_result[word_idx] >> shift) & u64(0xFFu));
        P[pwd_len - 1u - i] = byte_val;
    }

    let s_repeat_count = 16u + u32((alt_result[0u] >> 56u) & u64(0xFFu));
    temp_result = sha512_repeated_seq16(config.salt, config.salt_len, s_repeat_count);
    var S: array<u32, 16>;
    for (var i = 0u; i < 16u; i++) { S[i] = 0u; }
    for (var i = 0u; i < config.salt_len; i++) {
        let src_idx = i % 64u;
        let word_idx = src_idx / 8u;
        let shift = (7u - (src_idx % 8u)) * 8u;
        let byte_val = u32((temp_result[word_idx] >> shift) & u64(0xFFu));
        S[config.salt_len - 1u - i] = byte_val;
    }

    for (var cnt = 0u; cnt < ROUNDS; cnt++) {
        for (var i = 0u; i < 64u; i++) { msg[i] = 0u; }
        pos = 0u;

        if ((cnt & 1u) != 0u) {
            for (var i = 0u; i < pwd_len; i++) {
                set_byte_be64(&msg, pos + i, P[pwd_len - 1u - i] & 0xFFu);
            }
            pos += pwd_len;
        } else {
            for (var i = 0u; i < 8u; i++) {
                set_byte_be64(&msg, pos + i * 8u + 0u, u32((alt_result[i] >> 56u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 1u, u32((alt_result[i] >> 48u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 2u, u32((alt_result[i] >> 40u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 3u, u32((alt_result[i] >> 32u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 4u, u32((alt_result[i] >> 24u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 5u, u32((alt_result[i] >> 16u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 6u, u32((alt_result[i] >> 8u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 7u, u32(alt_result[i] & u64(0xFFu)));
            }
            pos += 64u;
        }

        if ((cnt % 3u) != 0u) {
            for (var i = 0u; i < config.salt_len; i++) {
                set_byte_be64(&msg, pos + i, S[config.salt_len - 1u - i] & 0xFFu);
            }
            pos += config.salt_len;
        }

        if ((cnt % 7u) != 0u) {
            for (var i = 0u; i < pwd_len; i++) {
                set_byte_be64(&msg, pos + i, P[pwd_len - 1u - i] & 0xFFu);
            }
            pos += pwd_len;
        }

        if ((cnt & 1u) != 0u) {
            for (var i = 0u; i < 8u; i++) {
                set_byte_be64(&msg, pos + i * 8u + 0u, u32((alt_result[i] >> 56u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 1u, u32((alt_result[i] >> 48u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 2u, u32((alt_result[i] >> 40u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 3u, u32((alt_result[i] >> 32u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 4u, u32((alt_result[i] >> 24u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 5u, u32((alt_result[i] >> 16u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 6u, u32((alt_result[i] >> 8u) & u64(0xFFu)));
                set_byte_be64(&msg, pos + i * 8u + 7u, u32(alt_result[i] & u64(0xFFu)));
            }
            pos += 64u;
        } else {
            for (var i = 0u; i < pwd_len; i++) {
                set_byte_be64(&msg, pos + i, P[pwd_len - 1u - i] & 0xFFu);
            }
            pos += pwd_len;
        }

        alt_result = sha512_bytes(msg, pos);
    }

    return alt_result;
}

fn check_match(hash: array<u64, 8>) -> bool {
    for (var t = 0u; t < config.num_targets; t++) {
        var t_match = true;
        for (var i = 0u; i < 8u; i++) {
            let low = u32(hash[i] & u64(0xFFFFFFFFu));
            let high = u32(hash[i] >> 32u);
            if (low != targets[t].hash[i]) { t_match = false; }
            if (high != targets[t].hash_extra[i]) { t_match = false; }
        }
        if (t_match) { return true; }
    }
    return false;
}

fn char_from_digit(d: u32) -> u32 {
    if (d < 26u) { return d + 97u; }
    else if (d < 52u) { return d - 26u + 65u; }
    else { return d - 52u + 48u; }
}

fn index_to_password(index: u32, len: u32) -> array<u32, 4> {
    var pwd: array<u32, 4>;
    var remaining = index;
    for (var i = 0u; i < 4u; i++) {
        if (i < len) {
            let d = remaining % CHARSET_SIZE;
            pwd[i] = char_from_digit(d);
            remaining = remaining / CHARSET_SIZE;
        } else { pwd[i] = 0u; }
    }
    return pwd;
}

const MAX_DISPATCH_X: u32 = 65535u;

@compute @workgroup_size(128)
fn main(@builtin(global_invocation_id) id: vec3<u32>) {
    let index = config.range_start + id.y * MAX_DISPATCH_X * 128u + id.x;
    if (index >= config.range_end) { return; }
    if (atomicLoad(&config.found_flag) != 0u) { atomicAdd(&progress.count, 1u); return; }    let pwd = index_to_password(index, config.password_len);
    let hash = sha512crypt_hash(pwd, config.password_len);
    if (check_match(hash)) {
        let prev = atomicCompareExchangeWeak(&config.found_flag, 0u, 1u);
        if (prev.old_value == 0u) { config.found_password = pwd; }
    }
    atomicAdd(&progress.count, 1u);
}