破解某法院网sign签名

Chan included in 2020 技术

2020-08-10 2117 words 5 minutes

Contents

::: tip 记录采集 XX法院网反爬虫sign验证签名 :::

签名验证反爬虫

签名验证的结果

签名是根据数据源进行计算或加密的过程，签名的结果是一个具有唯一性和一致性的字符串。签名结果的特征使得它成为验证数据来源和数据完整性的条件，可以有效避免服务器端将伪造的数据或篡改的数据当成正常数据处理。

签名验证的作用

签名验证时防止恶意连接和数据被篡改的有效方式之一，也是目前后端API最常见的防护方式之一。与Cookie，User-Aget，Host和Referer等请求头域不同，用于签名验证的信息通常被放在请求正文中发送到服务器端。

签名验证的方式

签名验证有很多种实现方式，但是原理都是相同的：由客服端生成一些随机值和不可逆的MD5加密字符串，并在发起请求时将这些值发送给服务器端。服务器端使用相同的方式对随机值进行计算以及MD5加密，如果服务器端得到的MD5值与前端提交的MD5值相同，就代表时正常请求，否则返回error或者403.

def sign(value):
    sign_v = hashlib.md5(value.encode(encoding="utf-8")).hexdigest()
    return sign_v

XX法院网

浏览器开发者模式断点调试, 分析生成签名的js相关代码, 漫长的分析, 分析步骤省略…

PY代码

python调用js, 生成sign签名

import hashlib
import execjs
import time

# 10位数时间戳
t = int(time.time())

with open('./chinacourt_sign.js', 'r', encoding='UTF-8') as f:
    js = f.read()

params = {
    "page": 1,
    "level": 3,
    "limit": 50,
    "startTime": "2021-01-26",
    "endTime": "2021-02-25",
    "versionNumber": "wap-v1"
}

ctx = execjs.compile(js)
data = ctx.call("MD5", params, t)
print(data)

输出

1614253292
{'page': 1, 'level': 3, 'limit': 50, 'startTime': '2021-01-26', 'endTime': '2021-02-25', 'versionNumber': 'wap-v1', 'signTime': 1614253292, 'sign': '6EF27CEFAE958CE1B1244CBF39FC563B'}

请求接口时带上sign签名与相关参数

JS代码

浏览器分析整理后合并的JS代码, 放在一个js文件, 方便调用

function MD5(params, t) {
    var signParam = ""; // 最终的sign
    var bandParam = "478226dd02d159fb0c6d7fc675629a12f8723ecd";
    var versionNumber = "wap-v1";
    // params["bandParam"] = bandParam;
    params["versionNumber"] = versionNumber;
    params["signTime"] = t;
    var sign = bandParam;
    var newData = []
    for (var item in params) {
        newData.push(item);
    }
    newData.sort()
    for (var i = 0; i < newData.length; i++) {
        if (
            Object.prototype.toString.call(params[newData[i]]) !==
            "[object Array]" &&
            Object.prototype.toString.call(params[newData[i]]) !== "[object Object]"
        ) {
            if (newData[i] !== "sign") {
                sign += newData[i] + params[newData[i]];
            }
        }
    }
    sign += bandParam;
    signParam = md5(sign).toUpperCase();
    params["sign"] = signParam;
    return params;
};

function safeAdd(x, y) {
    var lsw = (x & 0xffff) + (y & 0xffff);
    var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
    return (msw << 16) | (lsw & 0xffff);
}

/*
* Bitwise rotate a 32-bit number to the left.
*/
function bitRotateLeft(num, cnt) {
    return (num << cnt) | (num >>> (32 - cnt));
}

/*
* These functions implement the four basic operations the algorithm uses.
*/
function md5cmn(q, a, b, x, s, t) {
    return safeAdd(bitRotateLeft(safeAdd(safeAdd(a, q), safeAdd(x, t)), s), b);
}

function md5ff(a, b, c, d, x, s, t) {
    return md5cmn((b & c) | (~b & d), a, b, x, s, t);
}

function md5gg(a, b, c, d, x, s, t) {
    return md5cmn((b & d) | (c & ~d), a, b, x, s, t);
}

function md5hh(a, b, c, d, x, s, t) {
    return md5cmn(b ^ c ^ d, a, b, x, s, t);
}

function md5ii(a, b, c, d, x, s, t) {
    return md5cmn(c ^ (b | ~d), a, b, x, s, t);
}

/*
* Calculate the MD5 of an array of little-endian words, and a bit length.
*/
function binlMD5(x, len) {
    /* append padding */
    x[len >> 5] |= 0x80 << len % 32;
    x[(((len + 64) >>> 9) << 4) + 14] = len;

    var i;
    var olda;
    var oldb;
    var oldc;
    var oldd;
    var a = 1732584193;
    var b = -271733879;
    var c = -1732584194;
    var d = 271733878;

    for (i = 0; i < x.length; i += 16) {
        olda = a;
        oldb = b;
        oldc = c;
        oldd = d;

        a = md5ff(a, b, c, d, x[i], 7, -680876936);
        d = md5ff(d, a, b, c, x[i + 1], 12, -389564586);
        c = md5ff(c, d, a, b, x[i + 2], 17, 606105819);
        b = md5ff(b, c, d, a, x[i + 3], 22, -1044525330);
        a = md5ff(a, b, c, d, x[i + 4], 7, -176418897);
        d = md5ff(d, a, b, c, x[i + 5], 12, 1200080426);
        c = md5ff(c, d, a, b, x[i + 6], 17, -1473231341);
        b = md5ff(b, c, d, a, x[i + 7], 22, -45705983);
        a = md5ff(a, b, c, d, x[i + 8], 7, 1770035416);
        d = md5ff(d, a, b, c, x[i + 9], 12, -1958414417);
        c = md5ff(c, d, a, b, x[i + 10], 17, -42063);
        b = md5ff(b, c, d, a, x[i + 11], 22, -1990404162);
        a = md5ff(a, b, c, d, x[i + 12], 7, 1804603682);
        d = md5ff(d, a, b, c, x[i + 13], 12, -40341101);
        c = md5ff(c, d, a, b, x[i + 14], 17, -1502002290);
        b = md5ff(b, c, d, a, x[i + 15], 22, 1236535329);

        a = md5gg(a, b, c, d, x[i + 1], 5, -165796510);
        d = md5gg(d, a, b, c, x[i + 6], 9, -1069501632);
        c = md5gg(c, d, a, b, x[i + 11], 14, 643717713);
        b = md5gg(b, c, d, a, x[i], 20, -373897302);
        a = md5gg(a, b, c, d, x[i + 5], 5, -701558691);
        d = md5gg(d, a, b, c, x[i + 10], 9, 38016083);
        c = md5gg(c, d, a, b, x[i + 15], 14, -660478335);
        b = md5gg(b, c, d, a, x[i + 4], 20, -405537848);
        a = md5gg(a, b, c, d, x[i + 9], 5, 568446438);
        d = md5gg(d, a, b, c, x[i + 14], 9, -1019803690);
        c = md5gg(c, d, a, b, x[i + 3], 14, -187363961);
        b = md5gg(b, c, d, a, x[i + 8], 20, 1163531501);
        a = md5gg(a, b, c, d, x[i + 13], 5, -1444681467);
        d = md5gg(d, a, b, c, x[i + 2], 9, -51403784);
        c = md5gg(c, d, a, b, x[i + 7], 14, 1735328473);
        b = md5gg(b, c, d, a, x[i + 12], 20, -1926607734);

        a = md5hh(a, b, c, d, x[i + 5], 4, -378558);
        d = md5hh(d, a, b, c, x[i + 8], 11, -2022574463);
        c = md5hh(c, d, a, b, x[i + 11], 16, 1839030562);
        b = md5hh(b, c, d, a, x[i + 14], 23, -35309556);
        a = md5hh(a, b, c, d, x[i + 1], 4, -1530992060);
        d = md5hh(d, a, b, c, x[i + 4], 11, 1272893353);
        c = md5hh(c, d, a, b, x[i + 7], 16, -155497632);
        b = md5hh(b, c, d, a, x[i + 10], 23, -1094730640);
        a = md5hh(a, b, c, d, x[i + 13], 4, 681279174);
        d = md5hh(d, a, b, c, x[i], 11, -358537222);
        c = md5hh(c, d, a, b, x[i + 3], 16, -722521979);
        b = md5hh(b, c, d, a, x[i + 6], 23, 76029189);
        a = md5hh(a, b, c, d, x[i + 9], 4, -640364487);
        d = md5hh(d, a, b, c, x[i + 12], 11, -421815835);
        c = md5hh(c, d, a, b, x[i + 15], 16, 530742520);
        b = md5hh(b, c, d, a, x[i + 2], 23, -995338651);

        a = md5ii(a, b, c, d, x[i], 6, -198630844);
        d = md5ii(d, a, b, c, x[i + 7], 10, 1126891415);
        c = md5ii(c, d, a, b, x[i + 14], 15, -1416354905);
        b = md5ii(b, c, d, a, x[i + 5], 21, -57434055);
        a = md5ii(a, b, c, d, x[i + 12], 6, 1700485571);
        d = md5ii(d, a, b, c, x[i + 3], 10, -1894986606);
        c = md5ii(c, d, a, b, x[i + 10], 15, -1051523);
        b = md5ii(b, c, d, a, x[i + 1], 21, -2054922799);
        a = md5ii(a, b, c, d, x[i + 8], 6, 1873313359);
        d = md5ii(d, a, b, c, x[i + 15], 10, -30611744);
        c = md5ii(c, d, a, b, x[i + 6], 15, -1560198380);
        b = md5ii(b, c, d, a, x[i + 13], 21, 1309151649);
        a = md5ii(a, b, c, d, x[i + 4], 6, -145523070);
        d = md5ii(d, a, b, c, x[i + 11], 10, -1120210379);
        c = md5ii(c, d, a, b, x[i + 2], 15, 718787259);
        b = md5ii(b, c, d, a, x[i + 9], 21, -343485551);

        a = safeAdd(a, olda);
        b = safeAdd(b, oldb);
        c = safeAdd(c, oldc);
        d = safeAdd(d, oldd);
    }
    return [a, b, c, d];
}

/*
* Convert an array of little-endian words to a string
*/
function binl2rstr(input) {
    var i;
    var output = "";
    var length32 = input.length * 32;
    for (i = 0; i < length32; i += 8) {
        output += String.fromCharCode((input[i >> 5] >>> i % 32) & 0xff);
    }
    return output;
}

/*
* Convert a raw string to an array of little-endian words
* Characters >255 have their high-byte silently ignored.
*/
function rstr2binl(input) {
    var i;
    var output = [];
    output[(input.length >> 2) - 1] = undefined;
    for (i = 0; i < output.length; i += 1) {
        output[i] = 0;
    }
    var length8 = input.length * 8;
    for (i = 0; i < length8; i += 8) {
        output[i >> 5] |= (input.charCodeAt(i / 8) & 0xff) << i % 32;
    }
    return output;
}

/*
* Calculate the MD5 of a raw string
*/
function rstrMD5(s) {
    return binl2rstr(binlMD5(rstr2binl(s), s.length * 8));
}

/*
* Calculate the HMAC-MD5, of a key and some data (raw strings)
*/
function rstrHMACMD5(key, data) {
    var i;
    var bkey = rstr2binl(key);
    var ipad = [];
    var opad = [];
    var hash;
    ipad[15] = opad[15] = undefined;
    if (bkey.length > 16) {
        bkey = binlMD5(bkey, key.length * 8);
    }
    for (i = 0; i < 16; i += 1) {
        ipad[i] = bkey[i] ^ 0x36363636;
        opad[i] = bkey[i] ^ 0x5c5c5c5c;
    }
    hash = binlMD5(ipad.concat(rstr2binl(data)), 512 + data.length * 8);
    return binl2rstr(binlMD5(opad.concat(hash), 512 + 128));
}

/*
* Convert a raw string to a hex string
*/
function rstr2hex(input) {
    var hexTab = "0123456789abcdef";
    var output = "";
    var x;
    var i;
    for (i = 0; i < input.length; i += 1) {
        x = input.charCodeAt(i);
        output += hexTab.charAt((x >>> 4) & 0x0f) + hexTab.charAt(x & 0x0f);
    }
    return output;
}

/*
* Encode a string as utf-8
*/
function str2rstrUTF8(input) {
    return unescape(encodeURIComponent(input));
}

/*
* Take string arguments and return either raw or hex encoded strings
*/
function rawMD5(s) {
    return rstrMD5(str2rstrUTF8(s));
}

function hexMD5(s) {
    return rstr2hex(rawMD5(s));
}

function rawHMACMD5(k, d) {
    return rstrHMACMD5(str2rstrUTF8(k), str2rstrUTF8(d));
}

function hexHMACMD5(k, d) {
    return rstr2hex(rawHMACMD5(k, d));
}

function md5(string, key, raw) {
    if (!key) {
        if (!raw) {
            return hexMD5(string);
        }
        return rawMD5(string);
    }
    if (!raw) {
        return hexHMACMD5(key, string);
    }
    return rawHMACMD5(key, string);
}

if (typeof define === "function" && define.amd) {
    define(function () {
        return md5;
    });
} else if (typeof module === "object" && module.exports) {
    module.exports = md5;
} else {
    $.md5 = md5;
}