// skipqc
var sha256 = function a(b) {
    function c(a, b) {
        return (a >>> b) | (a << (32 - b))
    }
    for (
        var d,
            e,
            f = Math.pow,
            g = f(2, 32),
            h = 'length',
            i = '',
            j = [],
            k = 8 * b[h],
            l = (a.h = a.h || []),
            m = (a.k = a.k || []),
            n = m[h],
            o = {},
            p = 2;
        n < 64;
        p++
    )
        if (!o[p]) {
            for (d = 0; d < 313; d += p) o[d] = p
            ;(l[n] = (f(p, 0.5) * g) | 0), (m[n++] = (f(p, 1 / 3) * g) | 0)
        }
    for (b += '\x80'; (b[h] % 64) - 56; ) b += '\x00'
    for (d = 0; d < b[h]; d++) {
        if (((e = b.charCodeAt(d)), e >> 8)) return
        j[d >> 2] |= e << (((3 - d) % 4) * 8)
    }
    for (j[j[h]] = (k / g) | 0, j[j[h]] = k, e = 0; e < j[h]; ) {
        var q = j.slice(e, (e += 16)),
            r = l
        for (l = l.slice(0, 8), d = 0; d < 64; d++) {
            var s = q[d - 15],
                t = q[d - 2],
                u = l[0],
                v = l[4],
                w =
                    l[7] +
                    (c(v, 6) ^ c(v, 11) ^ c(v, 25)) +
                    ((v & l[5]) ^ (~v & l[6])) +
                    m[d] +
                    (q[d] =
                        d < 16
                            ? q[d]
                            : (q[d - 16] +
                                  (c(s, 7) ^ c(s, 18) ^ (s >>> 3)) +
                                  q[d - 7] +
                                  (c(t, 17) ^ c(t, 19) ^ (t >>> 10))) |
                              0),
                x =
                    (c(u, 2) ^ c(u, 13) ^ c(u, 22)) +
                    ((u & l[1]) ^ (u & l[2]) ^ (l[1] & l[2]))
            ;(l = [(w + x) | 0].concat(l)), (l[4] = (l[4] + w) | 0)
        }
        for (d = 0; d < 8; d++) l[d] = (l[d] + r[d]) | 0
    }
    for (d = 0; d < 8; d++)
        for (e = 3; e + 1; e--) {
            var y = (l[d] >> (8 * e)) & 255
            i += (y < 16 ? 0 : '') + y.toString(16)
        }
    return i
}

function hash(str, salt, num) {
    if (!num && num !== 0) num = 1
    if (!str) return
    if (!salt) salt = ''
    let ret = str
    for (let i = 0; i < num; i++) {
        ret = sha256(ret + salt)
    }
    return ret
}

function extend(key, len) {
    let temp = []
    let out = []

    len = len || 265

    let hashes = 0

    for (let i = 0; i < len / 64; i++) {
        temp[0] = hash(key, '', ++hashes)

        temp[1] = hash(key, '', ++hashes)

        temp[2] = hash(key, '', ++hashes)

        out[out.length] = hash(temp[0] + temp[1], temp[2], ++hashes)
        temp = []
    }

    return out.join('').substring(0, len)
}