JavaScript混淆器实现原理举例详解

// 原始代码
function calculateTotal(price, quantity) {
  const discount = 0.9;
  return price * quantity * discount;
}

// 混淆后
function _0x1a2b(_0x3c4d, _0x5e6f) {
  const _0x7g8h = 0.9;
  return _0x3c4d * _0x5e6f * _0x7g8h;
}

class IdentifierRenamer {
  private map = new Map<string, string>()
  private counter = 0
  
  rename(original: string): string {
    if (this.map.has(original)) {
      return this.map.get(original)!
    }
    const newName = `_0x${this.counter.toString(16)}`
    this.map.set(original, newName)
    this.counter++
    return newName
  }
}

// 原始代码
const message = "Hello, World!";
console.log("User: " + username);
alert("Operation completed");

// 混淆后
var _0x4f3a = ["Hello, World!", "User: ", "Operation completed"];
const message = _0x4f3a[0];
console.log(_0x4f3a[1] + username);
alert(_0x4f3a[2]);

// Base64 编码
var _0x4f3a = ["SGVsbG8sIFdvcmxkIQ==", "VXNlcjog", "T3BlcmF0aW9uIGNvbXBsZXRlZA=="];
function _0xdecode(idx) {
  return atob(_0x4f3a[idx]);
}

// RC4 加密（更难破解）
var _0x4f3a = ["\x1a\x2b\x3c...", "\x4d\x5e\x6f...", ...];
function _0xrc4(idx, key) {
  // RC4 解密逻辑
}

// 原始代码
function validate(user) {
  if (!user) return false;
  if (!user.email) return false;
  if (!user.password) return false;
  return true;
}

// 混淆后
function validate(user) {
  var _0xflow = "3|1|4|2|0".split("|");
  var _0xidx = 0;
  while (true) {
    switch (_0xflow[_0xidx++]) {
      case "0":
        return true;
      case "1":
        if (!user) return false;
        break;
      case "2":
        if (!user.password) return false;
        break;
      case "3":
        continue;
      case "4":
        if (!user.email) return false;
        break;
    }
    if (_0xidx >= _0xflow.length) break;
  }
}

// 原始代码
function add(a, b) {
  return a + b;
}

// 注入死代码后
function add(a, b) {
  if (typeof _0xdead === 'undefined') {
    var _0xfake1 = Math.random() * 1000;
    var _0xfake2 = "never executed";
    console.log(_0xfake1 + _0xfake2);
  }
  return a + b;
}

// 检测到调试器就无限循环
setInterval(function() {
  var start = Date.now();
  debugger;
  if (Date.now() - start > 100) {
    location.reload(); // 或者死循环
  }
}, 4000);

(function() {
  var _console = console;
  ['log', 'info', 'warn', 'error', 'debug'].forEach(function(method) {
    _console[method] = function() {};
  });
})();

// 格式化代码后会失效
(function() {
  function check() {
    var fn = function() {};
    fn.toString = function() {
      return '/* original code */';
    };
    if (fn + '' !== '/* original code */') {
      // 代码被修改了
      throw new Error('Tampered!');
    }
  }
  setInterval(check, 1000);
})();

(function() {
  var allowed = ['jsokit.com', '.jsokit.com'];
  var current = location.hostname;
  var valid = allowed.some(function(domain) {
    if (domain.startsWith('.')) {
      return current.endsWith(domain) || current === domain.slice(1);
    }
    return current === domain;
  });
  if (!valid) {
    // 不在允许的域名，停止执行
    return;
  }
})();

{
  compact: true,              // 压缩代码
  stringArray: true,          // 字符串数组化
  stringArrayThreshold: 0.5,  // 50% 字符串混淆
  controlFlowFlattening: false,
  deadCodeInjection: false
}

{
  compact: true,
  stringArray: true,
  stringArrayEncoding: ['base64'],
  stringArrayThreshold: 0.75,
  controlFlowFlattening: true,
  controlFlowFlatteningThreshold: 0.75,
  deadCodeInjection: true,
  deadCodeInjectionThreshold: 0.4
}

{
  compact: true,
  stringArray: true,
  stringArrayEncoding: ['rc4'],
  stringArrayThreshold: 1,
  controlFlowFlattening: true,
  controlFlowFlatteningThreshold: 1,
  deadCodeInjection: true,
  deadCodeInjectionThreshold: 1,
  debugProtection: true,
  selfDefending: true,
  disableConsoleOutput: true
}

// ❌ 危险：可能破坏第三方库
renameGlobals: true

// ✅ 安全：只混淆局部变量
renameGlobals: false

// 原始代码
eval("console.log('test')");

// 混淆后可能失败
eval("_0x1a2b('0x1')"); // _0x1a2b 在 eval 作用域不存在

// 原始代码
const obj = { name: 'John' };
console.log(obj.name);

// 混淆后
const obj = { _0x1a: 'John' };
console.log(obj._0x1a); // ❌ 错误：obj 没有 _0x1a 属性