网易云m4a音频链接获取请求头RSA加密

网址：https://music.163.com/#/song?id=186453

解析流程

通过歌曲的id获取歌曲的原链接

这是请求接口，很显然params和encSecKey是我们需要获取的，复制链接打上xhr断点，跟栈

断点打到这里，查看bMs8k是怎么一回事

控制台将几个参数都打印出来,一眼rsa加密

查看window.asrsea()方法，发现果然是rsa加密，直接扣代码，补全即可

var CryptoJS = require('crypto-js')

var d = '{"ids":"[3950292]","level":"standard","encodeType":"aac","csrf_token":""}',
    e = '010001',
    f = '00e0b509f6259df8642dbc35662901477df22677ec152b5ff68ace615bb7b725152b3ab17a876aea8a5aa76d2e417629ec4ee341f56135fccf695280104e0312ecbda92557c93870114af6c9d05c4f7f0c3685b7a46bee255932575cce10b424d813cfe4875d3e82047b97ddef52741d546b8e289dc6935b3ece0462db0a22b8e7',
    g = '0CoJUm6Qyw8W8jud'


function a(a) {
    var d, e, b = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789", c = "";
    for (d = 0; a > d; d += 1)
        e = Math.random() * b.length,
            e = Math.floor(e),
            c += b.charAt(e);
    return c
}

function b(a, b) {
    var c = CryptoJS.enc.Utf8.parse(b)
        , d = CryptoJS.enc.Utf8.parse("0102030405060708")
        , e = CryptoJS.enc.Utf8.parse(a)
        , f = CryptoJS.AES.encrypt(e, c, {
        iv: d,
        mode: CryptoJS.mode.CBC
    });
    return f.toString()
}

function charToHex(a) {
    var h, b = 48, c = b + 9, d = 97, e = d + 25, f = 65, g = 90;
    return h = a >= b && c >= a ? a - b : a >= f && g >= a ? 10 + a - f : a >= d && e >= a ? 10 + a - d : 0
}

function BarrettMu(a) {
    this.modulus = biCopy(a),
        this.k = biHighIndex(this.modulus) + 1;
    var b = new BigInt;
    b.digits[2 * this.k] = 1,
        this.mu = biDivide(b, this.modulus),
        this.bkplus1 = new BigInt,
        this.bkplus1.digits[this.k + 1] = 1,
        this.modulo = BarrettMu_modulo,
        this.multiplyMod = BarrettMu_multiplyMod,
        this.powMod = BarrettMu_powMod
}

function biCopy(a) {
    var b = new BigInt(!0);
    return b.digits = a.digits.slice(0),
        b.isNeg = a.isNeg,
        b
}

function biDivide(a, b) {
    return biDivideModulo(a, b)[0]
}

function biModulo(a, b) {
    return biDivideModulo(a, b)[1]
}

function biMultiplyMod(a, b, c) {
    return biModulo(biMultiply(a, b), c)
}

function biDivideModulo(a, b) {
    var f, g, h, i, j, k, l, m, n, o, p, q, r, s, c = biNumBits(a), d = biNumBits(b), e = b.isNeg;
    if (d > c)
        return a.isNeg ? (f = biCopy(bigOne),
            f.isNeg = !b.isNeg,
            a.isNeg = !1,
            b.isNeg = !1,
            g = biSubtract(b, a),
            a.isNeg = !0,
            b.isNeg = e) : (f = new BigInt,
            g = biCopy(a)),
            new Array(f, g);
    for (f = new BigInt,
             g = a,
             h = Math.ceil(d / bitsPerDigit) - 1,
             i = 0; b.digits[h] < biHalfRadix;)
        b = biShiftLeft(b, 1),
            ++i,
            ++d,
            h = Math.ceil(d / bitsPerDigit) - 1;
    for (g = biShiftLeft(g, i),
             c += i,
             j = Math.ceil(c / bitsPerDigit) - 1,
             k = biMultiplyByRadixPower(b, j - h); -1 != biCompare(g, k);)
        ++f.digits[j - h],
            g = biSubtract(g, k);
    for (l = j; l > h; --l) {
        for (m = l >= g.digits.length ? 0 : g.digits[l],
                 n = l - 1 >= g.digits.length ? 0 : g.digits[l - 1],
                 o = l - 2 >= g.digits.length ? 0 : g.digits[l - 2],
                 p = h >= b.digits.length ? 0 : b.digits[h],
                 q = h - 1 >= b.digits.length ? 0 : b.digits[h - 1],
                 f.digits[l - h - 1] = m == p ? maxDigitVal : Math.floor((m * biRadix + n) / p),
                 r = f.digits[l - h - 1] * (p * biRadix + q),
                 s = m * biRadixSquared + (n * biRadix + o); r > s;)
            --f.digits[l - h - 1],
                r = f.digits[l - h - 1] * (p * biRadix | q),
                s = m * biRadix * biRadix + (n * biRadix + o);
        k = biMultiplyByRadixPower(b, l - h - 1),
            g = biSubtract(g, biMultiplyDigit(k, f.digits[l - h - 1])),
        g.isNeg && (g = biAdd(g, k),
            --f.digits[l - h - 1])
    }
    return g = biShiftRight(g, i),
        f.isNeg = a.isNeg != e,
    a.isNeg && (f = e ? biAdd(f, bigOne) : biSubtract(f, bigOne),
        b = biShiftRight(b, i),
        g = biSubtract(b, g)),
    0 == g.digits[0] && 0 == biHighIndex(g) && (g.isNeg = !1),
        new Array(f, g)
}

function biShiftLeft(a, b) {
    var e, f, g, h, c = Math.floor(b / bitsPerDigit), d = new BigInt;
    for (arrayCopy(a.digits, 0, d.digits, c, d.digits.length - c),
             e = b % bitsPerDigit,
             f = bitsPerDigit - e,
             g = d.digits.length - 1,
             h = g - 1; g > 0; --g,
             --h)
        d.digits[g] = d.digits[g] << e & maxDigitVal | (d.digits[h] & highBitMasks[e]) >>> f;
    return d.digits[0] = d.digits[g] << e & maxDigitVal,
        d.isNeg = a.isNeg,
        d
}

function arrayCopy(a, b, c, d, e) {
    var g, h, f = Math.min(b + e, a.length);
    for (g = b,
             h = d; f > g; ++g,
             ++h)
        c[h] = a[g]
}

function biMultiplyDigit(a, b) {
    var c, d, e, f;
    for (result = new BigInt,
             c = biHighIndex(a),
             d = 0,
             f = 0; c >= f; ++f)
        e = result.digits[f] + a.digits[f] * b + d,
            result.digits[f] = e & maxDigitVal,
            d = e >>> biRadixBits;
    return result.digits[1 + c] = d,
        result
}

function biShiftRight(a, b) {
    var e, f, g, h, c = Math.floor(b / bitsPerDigit), d = new BigInt;
    for (arrayCopy(a.digits, c, d.digits, 0, a.digits.length - c),
             e = b % bitsPerDigit,
             f = bitsPerDigit - e,
             g = 0,
             h = g + 1; g < d.digits.length - 1; ++g,
             ++h)
        d.digits[g] = d.digits[g] >>> e | (d.digits[h] & lowBitMasks[e]) << f;
    return d.digits[d.digits.length - 1] >>>= e,
        d.isNeg = a.isNeg,
        d
}

function BarrettMu_modulo(a) {
    var i, b = biDivideByRadixPower(a, this.k - 1), c = biMultiply(b, this.mu), d = biDivideByRadixPower(c, this.k + 1),
        e = biModuloByRadixPower(a, this.k + 1), f = biMultiply(d, this.modulus),
        g = biModuloByRadixPower(f, this.k + 1), h = biSubtract(e, g);
    for (h.isNeg && (h = biAdd(h, this.bkplus1)),
             i = biCompare(h, this.modulus) >= 0; i;)
        h = biSubtract(h, this.modulus),
            i = biCompare(h, this.modulus) >= 0;
    return h
}

function BarrettMu_multiplyMod(a, b) {
    var c = biMultiply(a, b);
    return this.modulo(c)
}

function BarrettMu_powMod(a, b) {
    var d, e, c = new BigInt;
    for (c.digits[0] = 1,
             d = a,
             e = b; ;) {
        if (0 != (1 & e.digits[0]) && (c = this.multiplyMod(c, d)),
            e = biShiftRight(e, 1),
        0 == e.digits[0] && 0 == biHighIndex(e))
            break;
        d = this.multiplyMod(d, d)
    }
    return c
}

function biMultiply(a, b) {
    var d, h, i, k, c = new BigInt, e = biHighIndex(a), f = biHighIndex(b);
    for (k = 0; f >= k; ++k) {
        for (d = 0,
                 i = k,
                 j = 0; e >= j; ++j,
                 ++i)
            h = c.digits[i] + a.digits[j] * b.digits[k] + d,
                c.digits[i] = h & maxDigitVal,
                d = h >>> biRadixBits;
        c.digits[k + e + 1] = d
    }
    return c.isNeg = a.isNeg != b.isNeg,
        c
}

function biDivideByRadixPower(a, b) {
    var c = new BigInt;
    return arrayCopy(a.digits, b, c.digits, 0, c.digits.length - b),
        c
}

function biModuloByRadixPower(a, b) {
    var c = new BigInt;
    return arrayCopy(a.digits, 0, c.digits, 0, b),
        c
}

function biToHex(a) {
    var d, b = "";
    for (biHighIndex(a),
             d = biHighIndex(a); d > -1; --d)
        b += digitToHex(a.digits[d]);
    return b
}

function reverseStr(a) {
    var c, b = "";
    for (c = a.length - 1; c > -1; --c)
        b += a.charAt(c);
    return b
}

function digitToHex(a) {
    var b = 15
        , c = "";
    for (i = 0; 4 > i; ++i)
        c += hexToChar[a & b],
            a >>>= 4;
    return reverseStr(c)
}

var maxDigits, ZERO_ARRAY, bigZero, bigOne, dpl10, lr10, hexatrigesimalToChar, hexToChar, highBitMasks, lowBitMasks,
    biRadixBase = 2, biRadixBits = 16, bitsPerDigit = biRadixBits, biRadix = 65536, biHalfRadix = biRadix >>> 1,
    biRadixSquared = biRadix * biRadix, maxDigitVal = biRadix - 1, maxInteger = 9999999999999998;
setMaxDigits(20),
    dpl10 = 15,
    lr10 = biFromNumber(1e15),
    hexatrigesimalToChar = new Array("0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"),
    hexToChar = new Array("0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"),
    highBitMasks = new Array(0, 32768, 49152, 57344, 61440, 63488, 64512, 65024, 65280, 65408, 65472, 65504, 65520, 65528, 65532, 65534, 65535),
    lowBitMasks = new Array(0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535);

function biCompare(a, b) {
    if (a.isNeg != b.isNeg)
        return 1 - 2 * Number(a.isNeg);
    for (var c = a.digits.length - 1; c >= 0; --c)
        if (a.digits[c] != b.digits[c])
            return a.isNeg ? 1 - 2 * Number(a.digits[c] > b.digits[c]) : 1 - 2 * Number(a.digits[c] < b.digits[c]);
    return 0
}

function biSubtract(a, b) {
    var c, d, e, f;
    if (a.isNeg != b.isNeg)
        b.isNeg = !b.isNeg,
            c = biAdd(a, b),
            b.isNeg = !b.isNeg;
    else {
        for (c = new BigInt,
                 e = 0,
                 f = 0; f < a.digits.length; ++f)
            d = a.digits[f] - b.digits[f] + e,
                c.digits[f] = 65535 & d,
            c.digits[f] < 0 && (c.digits[f] += biRadix),
                e = 0 - Number(0 > d);
        if (-1 == e) {
            for (e = 0,
                     f = 0; f < a.digits.length; ++f)
                d = 0 - c.digits[f] + e,
                    c.digits[f] = 65535 & d,
                c.digits[f] < 0 && (c.digits[f] += biRadix),
                    e = 0 - Number(0 > d);
            c.isNeg = !a.isNeg
        } else
            c.isNeg = a.isNeg
    }
    return c
}

function biMultiplyByRadixPower(a, b) {
    var c = new BigInt;
    return arrayCopy(a.digits, 0, c.digits, b, c.digits.length - b),
        c
}

function biFromNumber(a) {
    var c, b = new BigInt;
    for (b.isNeg = 0 > a,
             a = Math.abs(a),
             c = 0; a > 0;)
        b.digits[c++] = a & maxDigitVal,
            a >>= biRadixBits;
    return b
}

function biNumBits(a) {
    var e, b = biHighIndex(a), c = a.digits[b], d = (b + 1) * bitsPerDigit;
    for (e = d; e > d - bitsPerDigit && 0 == (32768 & c); --e)
        c <<= 1;
    return e
}

function biHighIndex(a) {
    for (var b = a.digits.length - 1; b > 0 && 0 == a.digits[b];)
        --b;
    return b
}

function hexToDigit(a) {
    var d, b = 0, c = Math.min(a.length, 4);
    for (d = 0; c > d; ++d)
        b <<= 4,
            b |= charToHex(a.charCodeAt(d));
    return b
}

function biFromHex(a) {
    var d, e, b = new BigInt, c = a.length;
    for (d = c,
             e = 0; d > 0; d -= 4,
             ++e)
        b.digits[e] = hexToDigit(a.substr(Math.max(d - 4, 0), Math.min(d, 4)));
    return b
}

function BigInt(a) {
    this.digits = "boolean" == typeof a && 1 == a ? null : ZERO_ARRAY.slice(0),
        this.isNeg = !1
}

function setMaxDigits(a) {
    maxDigits = a,
        ZERO_ARRAY = new Array(maxDigits);
    for (var b = 0; b < ZERO_ARRAY.length; b++)
        ZERO_ARRAY[b] = 0;
    bigZero = new BigInt,
        bigOne = new BigInt,
        bigOne.digits[0] = 1
}

function RSAKeyPair(a, b, c) {
    this.e = biFromHex(a),
        this.d = biFromHex(b),
        this.m = biFromHex(c),
        this.chunkSize = 2 * biHighIndex(this.m),
        this.radix = 16,
        this.barrett = new BarrettMu(this.m)
}

function encryptedString(a, b) {
    for (var f, g, h, i, j, k, l, c = new Array, d = b.length, e = 0; d > e;)
        c[e] = b.charCodeAt(e),
            e++;
    for (; 0 != c.length % a.chunkSize;)
        c[e++] = 0;
    for (f = c.length,
             g = "",
             e = 0; f > e; e += a.chunkSize) {
        for (j = new BigInt,
                 h = 0,
                 i = e; i < e + a.chunkSize; ++h)
            j.digits[h] = c[i++],
                j.digits[h] += c[i++] << 8;
        k = a.barrett.powMod(j, a.e),
            l = 16 == a.radix ? biToHex(k) : biToString(k, a.radix),
            g += l + " "
    }
    return g.substring(0, g.length - 1)
}

function c(a, b, c) {
    var d, e;
    return setMaxDigits(131),
        d = new RSAKeyPair(b, "", c),
        e = encryptedString(d, a)
}


function encrypt(d) {
    var
    e = '010001',
    f = '00e0b509f6259df8642dbc35662901477df22677ec152b5ff68ace615bb7b725152b3ab17a876aea8a5aa76d2e417629ec4ee341f56135fccf695280104e0312ecbda92557c93870114af6c9d05c4f7f0c3685b7a46bee255932575cce10b424d813cfe4875d3e82047b97ddef52741d546b8e289dc6935b3ece0462db0a22b8e7',
    g = '0CoJUm6Qyw8W8jud'
    var h = {}
        , i = a(16);
    return h.encText = b(d, g),
        h.encText = b(h.encText, i),
        h.encSecKey = c(i, e, f), h
}

// var num1 = 3950292
//
// var result = encrypt(num1)
// console.log(result)
// var num1 = 3950292
// var d = '{"ids":"[${num1}]","level":"standard","encodeType":"aac","csrf_token":""}'
//
// console.log(d)