求助，内网里一个大系统的魔改国密算法

发表于: 2024-7-8 17:22 2331

求助，内网里一个大系统的魔改国密算法

中文名go

2024-7-8 17:22

2331

需求

我是想做爬虫的，但是这个算法确实搞不定，水平有限，而且我总觉得我的思路不对，希望算法和爬虫大佬能给一些指点和思路。
我不懂算法，我之前的经验都是js里的算法提出来翻译成python，但是这次这个确实是硬茬。

情况说明

系统使用的是国密算法，SM2，SM3，SM4。
网页框架是Vue.js。
提交数据是2个参数：data 和 privateParam
参数生成的方法如下：

e是原文，类似于{"mgtOrgCode":"123456"}

单步跟进发现算法是魔改的，我目前只看了SM3的，相关情况是：
SG_sm3encrypt进入后是Lr函数，然后进到vr里面算了一通，最后结果是个64位字符串，
我尝试用AI把js翻译成python，翻译了十几次都没有成功，错误的地方大概是：
1、ProcessBlock里的

1 2	`for` `e` `in` `range(16,` `68):` `t.append(self.P1(t[e` `-` `16] ^ t[e` `-` `9] ^ Fr(t[e` `-` `3],` `15)) ^ Fr(t[e` `-` `13],` `7) ^ t[e` `-` `6])`

Fr(t[e - 3]出现index溢出

2、GetHex的

for o in range(0, 2 * len(e), 2):
    t[o >> 3] |= int(e[r]) << (24 - o % 8 * 4)
    r += 1

t[o >> 3]出现index溢出

3、死循环，算不出来。
下面我会把代码贴上。

代码部分

1、Lr函数如下：

function Lr(e) {
            if (void 0 != e && "" != e) {
                var t = S.enc.Utf8.parse(e)
                  , r = new vr;
                t = r.GetWords(t.toString()),
                r.BlockUpdate(t, 0, t.length);
                var o = new Array(32);
                r.DoFinal(o, 0);
                var n = r.GetHex(o).toString();
                return n
            }
        }

2、vr的结构如下：

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function vr() {
    this.BYTE_LENGTH = 64,
        this.xBuf = [],
        this.xBufOff = 0,
        this.byteCount = 0,
        this.DIGEST_LENGTH = 32,
        this.v0 = [1937774191, 1226093241, 388252375, -628488704, -1452330820, 372324522, -477237683, -1325724082],
        this.v = [0, 0, 0, 0, 0, 0, 0, 0],
        this.v_ = [0, 0, 0, 0, 0, 0, 0, 0],
        this.X0 = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
        this.X = [68],
        this.xOff = 0,
        this.T_00_15 = 2043430169,
        this.T_16_63 = 2055708042,
        arguments.length > 0 ? this.InitDigest(arguments[0]) : this.Init()
}
 
vr.prototype = {
    Init: function () {
        this.xBuf = [0, 0, 0, 0],
            this.Reset()
    },
    InitDigest: function (e) {
        this.xBuf = [e.xBuf.length],
            Array.Copy(e.xBuf, 0, this.xBuf, 0, e.xBuf.length),
            this.xBufOff = e.xBufOff,
            this.byteCount = e.byteCount,
            Array.Copy(e.X, 0, this.X, 0, e.X.length),
            this.xOff = e.xOff,
            Array.Copy(e.v, 0, this.v, 0, e.v.length)
    },
    GetDigestSize: function () {
        return this.DIGEST_LENGTH
    },
    Reset: function () {
        this.byteCount = 0,
            this.xBufOff = 0,
            Array.Clear(this.xBuf, 0, this.xBuf.length),
            Array.Copy(this.v0, 0, this.v, 0, this.v0.length),
            this.xOff = 0,
            Array.Copy(this.X0, 0, this.X, 0, this.X0.length)
    },
    GetByteLength: function () {
        return this.BYTE_LENGTH
    },
    ProcessBlock: function () {
        var e, t = this.X, r = [64];
        for (e = 16; e < 68; e += 1)
            t[e] = this.P1(t[e - 16] ^ t[e - 9] ^ Fr(t[e - 3], 15)) ^ Fr(t[e - 13], 7) ^ t[e - 6];
        for (e = 0; e < 64; e += 1)
            r[e] = t[e] ^ t[e + 4];
        var o, n, i, s, a, u = this.v, c = this.v_;
        for (Array.Copy(u, 0, c, 0, this.v0.length),
            e = 0; e < 16; e += 1)
            a = Fr(c[0], 12),
                o = a + c[4] + Fr(this.T_00_15, e),
                o = Fr(o, 7),
                n = o ^ a,
                i = this.FF_00_15(c[0], c[1], c[2]) + c[3] + n + r[e],
                s = this.GG_00_15(c[4], c[5], c[6]) + c[7] + o + t[e],
                c[3] = c[2],
                c[2] = Fr(c[1], 9),
                c[1] = c[0],
                c[0] = i,
                c[7] = c[6],
                c[6] = Fr(c[5], 19),
                c[5] = c[4],
                c[4] = this.P0(s);
        for (e = 16; e < 64; e += 1)
            a = Fr(c[0], 12),
                o = a + c[4] + Fr(this.T_16_63, e),
                o = Fr(o, 7),
                n = o ^ a,
                i = this.FF_16_63(c[0], c[1], c[2]) + c[3] + n + r[e],
                s = this.GG_16_63(c[4], c[5], c[6]) + c[7] + o + t[e],
                c[3] = c[2],
                c[2] = Fr(c[1], 9),
                c[1] = c[0],
                c[0] = i,
                c[7] = c[6],
                c[6] = Fr(c[5], 19),
                c[5] = c[4],
                c[4] = this.P0(s);
        for (e = 0; e < 8; e += 1)
            u[e] ^= c[e];
        this.xOff = 0,
            Array.Copy(this.X0, 0, this.X, 0, this.X0.length)
    },
    ProcessWord: function (e, t) {
        var r = e[t] << 24;
        r |= (255 & e[t += 1]) << 16,
            r |= (255 & e[t += 1]) << 8,
            r |= 255 & e[t += 1],
            this.X[this.xOff] = r,
            16 == ++this.xOff && this.ProcessBlock()
    },
    ProcessLength: function (e) {
        this.xOff > 14 && this.ProcessBlock(),
            this.X[14] = this.URShiftLong(e, 32),
            this.X[15] = 4294967295 & e
    },
    IntToBigEndian: function (e, t, r) {
        t[r] = e >>> 24 & 255,
            t[r += 1] = e >>> 16 & 255,
            t[r += 1] = e >>> 8 & 255,
            t[r += 1] = 255 & e
    },
    DoFinal: function (e, t) {
        this.Finish();
        for (var r = 0; r < 8; r += 1)
            this.IntToBigEndian(this.v[r], e, t + 4 * r);
        return this.Reset(),
            this.DIGEST_LENGTH
    },
    Update: function (e) {
        this.xBuf[this.xBufOff++] = e,
            this.xBufOff == this.xBuf.length && (this.ProcessWord(this.xBuf, 0),
                this.xBufOff = 0),
            this.byteCount++
    },
    BlockUpdate: function (e, t, r) {
        while (0 != this.xBufOff && r > 0)
            this.Update(e[t]),
                t += 1,
                r -= 1;
        while (r > this.xBuf.length)
            this.ProcessWord(e, t),
                t += this.xBuf.length,
                r -= this.xBuf.length,
                this.byteCount += this.xBuf.length;
        while (r > 0)
            this.Update(e[t]),
                t += 1,
                r -= 1
    },
    Finish: function () {
        var e = this.byteCount << 3;
        this.Update(128);
        while (0 != this.xBufOff)
            this.Update(0);
        this.ProcessLength(e),
            this.ProcessBlock()
    },
    ROTATE: function (e, t) {
        return e << t | this.URShift(e, 32 - t)
    },
    P0: function (e) {
        return e ^ Fr(e, 9) ^ Fr(e, 17)
    },
    P1: function (e) {
        return e ^ Fr(e, 15) ^ Fr(e, 23)
    },
    FF_00_15: function (e, t, r) {
        return e ^ t ^ r
    },
    FF_16_63: function (e, t, r) {
        return e & t | e & r | t & r
    },
    GG_00_15: function (e, t, r) {
        return e ^ t ^ r
    },
    GG_16_63: function (e, t, r) {
        return e & t | ~e & r
    },
    URShift: function (e, t) {
        return console.error(e),
            (e > Int32.maxValue || e < Int32.minValue) && (console.error(e),
                e = Cr(e)),
            e >= 0 ? e >> t : (e >> t) + (2 << ~t)
    },
    URShiftLong: function (e, t) {
        var r, o = new E;
        if (o.fromInt(e),
            o.signum() >= 0)
            r = o.shiftRight(t).intValue();
        else {
            var n = new E;
            n.fromInt(2);
            var i = ~t
                , s = "";
            if (i < 0) {
                for (var a = 64 + i, u = 0; u < a; u += 1)
                    s += "0";
                var c = new E;
                c.fromInt(e >> t);
                var l = new E("10" + s, 2);
                s = l.toRadix(10);
                var f = l.add(c);
                r = f.toRadix(10)
            } else
                s = n.shiftLeft(~t).intValue(),
                    r = (e >> t) + s
        }
        return r
    },
    GetZ: function (e, t, r) {
        var o = S.enc.Utf8.parse(r)
            , n = 4 * o.words.length * 8;
        this.Update(n >> 8 & 255),
            this.Update(255 & n);
        var i = this.GetWords(o.toString());
        this.BlockUpdate(i, 0, i.length);
        var s = this.GetWords(e.curve.a.toBigInteger().toRadix(16))
            , a = this.GetWords(e.curve.b.toBigInteger().toRadix(16))
            , u = this.GetWords(e.getX().toBigInteger().toRadix(16))
            , c = this.GetWords(e.getY().toBigInteger().toRadix(16))
            , l = this.GetWords(t.substr(0, 64))
            , f = this.GetWords(t.substr(64, 64));
        this.BlockUpdate(s, 0, s.length),
            this.BlockUpdate(a, 0, a.length),
            this.BlockUpdate(u, 0, u.length),
            this.BlockUpdate(c, 0, c.length),
            this.BlockUpdate(l, 0, l.length),
            this.BlockUpdate(f, 0, f.length);
        var h = [this.GetDigestSize()];
        return this.DoFinal(h, 0),
            h
    },
    GetWords: function (e) {
        for (var t = [], r = e.length, o = 0; o < r; o += 2)
            t[t.length] = parseInt(e.substr(o, 2), 16);
        return t
    },
    GetHex: function (e) {
        for (var t = [], r = 0, o = 0; o < 2 * e.length; o += 2)
            t[o >>> 3] |= parseInt(e[r]) << 24 - o % 8 * 4,
                r += 1;
        var n = new S.lib.WordArray.init(t, e.length);
        return n
    }
}

3、vr内的Fr函数如下

function Fr(e, t) {
            return e << t | e >>> -t
        }

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