JS代码混淆初步

一直以来，JS前端代码因为必须经过IE明文解析，某些加密的JS如：JScript.Encode也因为树大招风，早就被人破解了。还有些加密的手段，通过复杂的变换，改变源码，但最终都逃不脱最后的审判，像unescape,document.write,eval语句来还原。对于JS代码的保护，最好的手段就是混淆，混淆的目的就是让读懂代码的成本比直接写代码的成本高，混淆不是不可破解的，只是增加破解成本,JAVA,C#的加密都是采用混淆。这样对于非常核心的代码，混淆起不到保护代码的作用，不过JS有这样的代码么？本程序没有用到编译原理，其分词解析思想是基于mechiland( http://www.jzchen.net)的代码高亮程序，参考了蓝色经典的 加密混淆专题讨论。

< HTML >< HEAD >< TITLE > Cunfusion </ TITLE >
< META  content ="MSHTML 6.00.2800.1528"  name =GENERATOR >
< META  content =""  name =Author >
< META  content =""  name =Keywords >
< META  content =""  name =Description ></ HEAD >
< BODY >
< SCRIPT  language =JavaScript >
<!--
/**//**//**//** 
**    ==================================================================================================  
**    类名：CLASS_CONFUSION
**    功能：JS混淆  
**    示例：  
    ---------------------------------------------------------------------------------------------------  
  
            var xx        = new CLASS_CONFUSION(code);            

            document.getElementById("display").innerHTML = xx.confusion(); 
  
    ---------------------------------------------------------------------------------------------------  
**    作者：ttyp  
**    邮件：[email protected]  
**    日期：2006-3-20  
**    版本：0.12
**    ==================================================================================================  
**/  

function CLASS_CONFUSION(code){
    //哈希表类
    function Hashtable(){
        this._hash        = new Object();
        this.add        = function(key,value){
                            if(typeof(key)!="undefined"){
                                if(this.contains(key)==false){
                                    this._hash[key]=typeof(value)=="undefined"?null:value;
                                    return true;
                                } else {
                                    return false;
                                }
                            } else {
                                return false;
                            }
                        }
        this.remove        = function(key){delete this._hash[key];}
        this.count        = function(){var i=0;for(var k in this._hash){i++;} return i;}
        this.items        = function(key){return this._hash[key];}
        this.contains    = function(key){return typeof(this._hash[key])!="undefined";}
        this.clear        = function(){for(var k in this._hash){delete this._hash[k];}}

    }

    function VariableMap(parent){
        this.table = new Hashtable();
        this.level = parent?parent.level+1:0;
        this.parent= parent;
        this.add = function(key,value){this.table.add(key,value)};
        this.items = function(key){return this.table.items(key)};
        this.count = function(){return this.table.count()};
        this.contains = function(key){return this.table.contains(key);}
        this.isParameter    = false;
    }

    this._caseSensitive = true;

    //字符串转换为哈希表
    this.str2hashtable = function(key,cs){
        
        var _key    = key.split(/,/g);
        var _hash    = new Hashtable(); 
        var _cs        = true;

    
        if(typeof(cs)=="undefined"||cs==null){
            _cs = this._caseSensitive;
        } else {
            _cs = cs;
        }

        for(var i in _key){
            if(_cs){
                _hash.add(_key[i]);
            } else {
                _hash.add((_key[i]+"").toLowerCase());
            }

        }
        return _hash;
    }

    //获得需要转换的代码
    this._codetxt        = code;

    if(typeof(syntax)=="undefined"){
        syntax = "";
    }

    this._deleteComment = false;
    //是否大小写敏感
    this._caseSensitive    = true;
    //得到关键字哈希表
    this._keywords        = this.str2hashtable("switch,case,delete,default,typeof,for,in,function,void,this,boolean,while,if,return,new,true,false,try,catch,throw,null,else,do,var");
    this._function        = this.str2hashtable("function");
    this._var            = "var";
    this._beginBlock    = "{";
    this._endBlock        = "}";
    
    this._window        = this.str2hashtable("alert,escape,unescape,document,parseInt,parseFloat");
    //得到内建对象哈希表
    this._commonObjects = this.str2hashtable("String,Number,Boolean,RegExp,Error,Math,Date,Object,Array,Global");
    //得到分割字符
    this._wordDelimiters= "　 ,.?!;:\\/<>(){}[]\"'\r\n\t=+-|*%@#$^&";
    //引用字符
    this._quotation        = this.str2hashtable("\",'");
    //行注释字符
    this._lineComment    = "//";
    //转义字符
    this._escape        = "\\";
    //多行引用开始
    this._commentOn        = "/*";
    //多行引用结束
    this._commentOff    = "*/";
    this._execute        = "eval";
    //引用调用字符
    this._call            = ".";
    this._varPause        = "=";
    this._varContinue    = ",";
    //变量个数
    this._varNum = 0;

    this.confusion    = function() {
        var codeArr = new Array();
        var word_index = 0;
        var htmlTxt = new Array();


        //得到分割字符数组(分词)
        for (var i = 0; i < this._codetxt.length; i++) {
            
            if (this._wordDelimiters.indexOf(this._codetxt.charAt(i)) == -1) {        //找不到关键字
                if (codeArr[word_index] == null || typeof(codeArr[word_index]) == 'undefined') {
                    codeArr[word_index] = "";
                }
                codeArr[word_index] += this._codetxt.charAt(i);
            } else {
                if (typeof(codeArr[word_index]) != 'undefined' && codeArr[word_index].length > 0)
                    word_index++;
                codeArr[word_index++] = this._codetxt.charAt(i);                
            } 
        }


        var quote_opened                = false;    //引用标记
        var slash_star_comment_opened    = false;    //多行注释标记
        var slash_slash_comment_opened    = false;    //单行注释标记
        var line_num                    = 1;        //行号
        var quote_char                    = "";        //引用标记类型
        var call_opened                    = false;
        var call_string                    = "";
        var var_opened                    = false;
        var var_pause                    = false;
        var function_opened                = false;
        var parameter_opened            = false;

        var var_map                        = new VariableMap();
        var cur_var_map                    = var_map;
        var execute_opened                = false;

        //按分割字，分块显示
        for (var i=0; i <=word_index; i++){

            //单独处理指针引用
            if(call_opened&&typeof(codeArr[i])!="undefined"){                
                if(call_string.length==0){
                    if(this.isVar(codeArr[i])){
                        call_string +=codeArr[i];
                    }else{
                        htmlTxt[htmlTxt.length] = "[\"" + this.toHex(call_string) + "\"]";
                        if(codeArr[i]!=this._call){
                            htmlTxt[htmlTxt.length] = codeArr[i];                        
                            call_opened = false;        
                        }
                        call_string = "";
                    }
                } else {
                    if(!this.isVar(codeArr[i])){
                        htmlTxt[htmlTxt.length] = "[\"" + this.toHex(call_string) + "\"]";
                        if(codeArr[i]!=this._call){
                            htmlTxt[htmlTxt.length] = codeArr[i];                            
                            call_opened = false;    
                        }
                        call_string = "";
                    }else{
                        htmlTxt[htmlTxt.length] = "[\"" + this.toHex(call_string) + "\"]";
                    }
                }
                continue;
            }
            
            //处理空行（由于转义带来）
            if(typeof(codeArr[i])=="undefined"||codeArr[i].length==0){
                continue;
            } else if(codeArr[i]==" "){
                htmlTxt[htmlTxt.length] = " ";
            } else if(codeArr[i]=="\n"){
            //处理换行
            } else if (codeArr[i] == "\r"){                                                                    
                slash_slash_comment_opened = false;        
                quote_opened = false;
                var_opened = false;
                htmlTxt[htmlTxt.length] = "\r\n";    
                line_num++;
            //处理function里的参数标记
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&this.isFunction(codeArr[i])){
                htmlTxt[htmlTxt.length] = codeArr[i];
                function_opened = true;
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&codeArr[i]=="("){
                htmlTxt[htmlTxt.length] = codeArr[i];
                if(function_opened == true){
                    function_opened =false;
                    var_opened = true;
                    cur_var_map = new VariableMap(cur_var_map);
                    cur_var_map.isParameter = true;
                }
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&codeArr[i]==")"){
                htmlTxt[htmlTxt.length] = codeArr[i];
                //处理var a = new Class(),b=new Date();类似的问题
                if(cur_var_map.isParameter){
                    var_opened = false;
                    var_pause = false;
                }
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&codeArr[i]==";"){
                htmlTxt[htmlTxt.length] = codeArr[i];
                var_opened = false;
                var_pause = false;
                if(execute_opened){    
                    execute_opened = false;
                }
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&codeArr[i]==this._var){
                htmlTxt[htmlTxt.length] = codeArr[i];
                var_opened = true;
                var_pause = false;
            } else if(!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&codeArr[i]==this._varPause){
                htmlTxt[htmlTxt.length] = codeArr[i];
                var_pause = true;
            } else if(!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&codeArr[i]==this._varContinue){
                htmlTxt[htmlTxt.length] = codeArr[i];
                var_pause = false;
            } else if(!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&codeArr[i]==this._beginBlock){
                cur_var_map = new VariableMap(cur_var_map);
                var_opened = false;
                htmlTxt[htmlTxt.length] = codeArr[i];
            } else if(!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&codeArr[i]==this._endBlock){
                cur_var_map = cur_var_map.parent;
                if(cur_var_map.isParameter){
                    cur_var_map = cur_var_map.parent;
                }
                htmlTxt[htmlTxt.length] = codeArr[i];
            //处理引用调用
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened &&codeArr[i]==this._call){
                //判断引用(.)后面第一个是否为字母货_$
                if(i<word_index-1){
                    if(this.isVar(codeArr[i+1])){                        
                        if(call_opened){
                            htmlTxt[htmlTxt.length] = this.toHex(call_string);
                        }
                        call_opened = true;    
                    }else{
                        htmlTxt[htmlTxt.length] = this._call;
                    }
                }else{
                    htmlTxt[htmlTxt.length] = this._call;
                }
            //处理关键字
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened && this.isKeyword(codeArr[i])){        
              htmlTxt[htmlTxt.length] = codeArr[i];
            //处理eval后的字符串
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened && codeArr[i]==this._execute){        
              htmlTxt[htmlTxt.length] = "window[\"" + this.toHex(codeArr[i]) + "\"]";
              execute_opened = true;
            //window内置对象
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened && this.isWindow(codeArr[i])){        
              htmlTxt[htmlTxt.length] = "window[\"" + this.toHex(codeArr[i]) + "\"]";
            //处理普通对象
            } else if (!slash_slash_comment_opened&&!slash_star_comment_opened && !quote_opened && this.isCommonObject(codeArr[i])){    
                htmlTxt[htmlTxt.length] =  "window[\"" + this.toHex(codeArr[i]) + "\"]";
            //处理双引号（引号前不能为转义字符）    
            } else if (!slash_star_comment_opened&&!slash_slash_comment_opened&&this._quotation.contains(codeArr[i])){                                                    
                if (quote_opened){
                    //是相应的引号
                    if(quote_char==codeArr[i]){
                        htmlTxt[htmlTxt.length] = codeArr[i];                    
                        quote_opened    = false;
                        quote_char        = "";
                    } else {
                        htmlTxt[htmlTxt.length] = this.toHex(codeArr[i]);            
                    }
                } else {
                    htmlTxt[htmlTxt.length] =  codeArr[i];
                    quote_opened    = true;
                    quote_char        = codeArr[i];
                }                    
            //处理转义字符
            } else if(codeArr[i] == this._escape){    
                htmlTxt[htmlTxt.length] = codeArr[i]; 
                if(i<word_index-1){
                    if(codeArr[i+1].charCodeAt(0)>=32&&codeArr[i+1].charCodeAt(0)<=127){
                        htmlTxt[htmlTxt.length] = codeArr[i+1].substr(0,1);
                        htmlTxt[htmlTxt.length] = this.toHex(codeArr[i+1].substr(1));
                        i=i+1;
                    }
                }            
            //处理多行注释的开始
            } else if (!slash_slash_comment_opened && !slash_star_comment_opened&&!quote_opened&&this.isStartWith(this._commentOn,codeArr,i)){                                                
                slash_star_comment_opened = true;
                htmlTxt[htmlTxt.length] = this._commentOn;
                i = i + this.getSkipLength(this._commentOn);    
            //处理单行注释
            } else if (!slash_slash_comment_opened && !slash_star_comment_opened&&!quote_opened&&this.isStartWith(this._lineComment,codeArr,i)){                                                
                slash_slash_comment_opened = true;
                if(!this._deleteComment){
                    htmlTxt[htmlTxt.length] =  this._lineComment;
                }
                i = i + this.getSkipLength(this._lineComment);    
            //处理忽略词
            } else if (!slash_slash_comment_opened && !slash_star_comment_opened&&!quote_opened&&this.isStartWith(this._ignore,codeArr,i)){                                                
                slash_slash_comment_opened = true;
                htmlTxt[htmlTxt.length] = this._ignore;
                i = i + this.getSkipLength(this._ignore);                    
            //处理多行注释结束    
            } else if (!quote_opened&&!slash_slash_comment_opened&&this.isStartWith(this._commentOff,codeArr,i)){                                
                if (slash_star_comment_opened) {
                    slash_star_comment_opened = false;
                    if(!this._deleteComment){
                        htmlTxt[htmlTxt.length] =  this._commentOff;
                    }
                    i = i + this.getSkipLength(this._commentOff);        
                }
            } else {
                //不是在字符串中
                if(!quote_opened){
                    //如果不是在注释重
                    if(!slash_slash_comment_opened && !slash_star_comment_opened){    
                        //不是在定义变量时
                        if(!var_opened){
                            if(this.translateVar(cur_var_map,codeArr[i])==""){
                                htmlTxt[htmlTxt.length] = codeArr[i];
                            }else{
                                htmlTxt[htmlTxt.length] = this.translateVar(cur_var_map,codeArr[i]);
                            }
                        }else{
                            //不是在暂停变量定义时
                            if(var_pause){
                                if(this.translateVar(cur_var_map,codeArr[i])==""){
                                    htmlTxt[htmlTxt.length] = codeArr[i];
                                }else{
                                    htmlTxt[htmlTxt.length] = this.translateVar(cur_var_map,codeArr[i]);
                                }                                
                            }else{
                                //变量符合命名规则，并且（变量前为空格或制表符或逗号如：var a;var    a;var a,b;，还有如果是函数参数,如：function(a,b,c)
                                if(this.isVar(codeArr[i])&&(i>0&&codeArr[i-1]==" "||codeArr[i-1]=="\t"||codeArr[i-1]==this._varContinue||cur_var_map.isParameter)){
                                    var name = this.getRandName();                                
                                    cur_var_map.add(codeArr[i],name);
                                    htmlTxt[htmlTxt.length] = this.translateVar(cur_var_map,codeArr[i]);
                                }else{
                                    htmlTxt[htmlTxt.length] = codeArr[i];
                                }
                            }
                        }
                    //注释中                            
                    }else{
                        if(!this._deleteComment){
                            htmlTxt[htmlTxt.length] = codeArr[i];
                        }
                    }
                }else{
                    if(execute_opened){
                        if(this.translateVar(cur_var_map,codeArr[i])==""){
                            htmlTxt[htmlTxt.length] = codeArr[i];
                        }else{
                            htmlTxt[htmlTxt.length] = this.translateVar(cur_var_map,codeArr[i]);
                        }
                    }else{
                        htmlTxt[htmlTxt.length] = this.toHex(codeArr[i]);
                    }
                }
            }
            
        }

        return htmlTxt.join("");
    }

    this.isStartWith = function(str,code,index){

        if(typeof(str)!="undefined"&&str.length>0){        
            var cc = new Array();            
            for(var i=index;i<index+str.length;i++){
                cc[cc.length] = code[i];
            }
            var c = cc.join("");
            if(this._caseSensitive){
                if(str.length>=code[index].length&&c.indexOf(str)==0){
                    return true;
                }
            }else{
                if(str.length>=code[index].length&&c.toLowerCase().indexOf(str.toLowerCase())==0){
                    return true;
                }
            }
            return false;

        } else {
            return false;
        }
    }

    this.isFunction = function(val){
        return this._function.contains(this._caseSensitive?val:val.toLowerCase());
    }
    
    this.isKeyword = function(val) {        
        return this._keywords.contains(this._caseSensitive?val:val.toLowerCase());
    }

    this.isWindow = function(val) {        
        return this._window.contains(this._caseSensitive?val:val.toLowerCase());
    }

    this.isCommonObject = function(val) {
        return this._commonObjects.contains(this._caseSensitive?val:val.toLowerCase());
    }

    this.getSkipLength = function(val){    
        var count = 0;
        for(var i=0;i<val.length;i++){
            if(this._wordDelimiters.indexOf(val.charAt(i))>=0){
                count++;
            }
        }
        if(count>0){
            count=count-1;
        }
        return count;
    }

    //字符串转换为16进制形式
    this.toHex = function(val){
        var str = new Array();
        for(var i=0;i<val.length;i++){
            var c = val.charCodeAt(i);
            if(c>=0&&c<256){
                str[str.length] = "\\x" + val.charCodeAt(i).toString(16);
            }else{
                str[str.length] = "\\u" + val.charCodeAt(i).toString(16);
            }
        }
        return str.join("");
    }

    //获得变量随机名
    this.getRandName = function(){
        var style = parseInt(Math.random()*4);
        var len = parseInt(Math.random()*9)+1;
        var n = [];

        this._varNum++;
        var c = "abcdefghijklmnopqrstuvwsyzABCDEFGHIJKLMNOPQRSTUVWXYZ_$";

        for(var i=0;i<len;i++){
            n[n.length] = c.charAt(parseInt(Math.random()*54)); 
        }

        return n.join("")+this._varNum;

    }

    //是否符合变量命名字首规则
    this.isVar = function(val){
        return /^[a-zA-Z_\$].*$/.test(val);
    }

    //翻译变量，如果返回为空则不存在此变量
    this.translateVar = function(node,key){
        if(node.contains(key)){
            return node.items(key);
        }

        var cn = node.parent;
        while(cn!=null){
            if(cn.contains(key)){
                return cn.items(key);
            }
            cn = cn.parent;        
        }
        return "";    
    }


}

function doConfusion(o){
    var htmltxt = "";

    if (o == null){
        alert("domNode is null!");
        return;
    }

    var _codetxt = "";
    
    if(typeof(o)=="object"){
        switch(o.tagName){
            case "TEXTAREA":
            case "INPUT":
                _codetxt = o.value;
                break;
            case "DIV":
            case "SPAN":
                _codetxt = o.innerText;
                break;
            default:
                _codetxt = o.innerHTML;
                break;
        }
    }else{
        _codetxt = o;
    }

    var _syn = new CLASS_CONFUSION(_codetxt);
    htmltxt = _syn.confusion();
    return  htmltxt;
}


function go()
{
    var code    = document.getElementById("code").value;
    var xx      = new CLASS_CONFUSION(code);    
    var a       = new Date();
    document.getElementById("display").value = xx.confusion();
    alert("共花：" + (new Date().getTime()-a.getTime()) + "ms");
}
//-->
</ SCRIPT >
< TEXTAREA  id =code  rows =12  cols =100 >
/*
这个是一个类
*/
function xx(num,str)
{
//说明
var a = num;
this.aa = a;
this.bb = function(){alert(str);}
this.cc = function(){for(var i=0;i < 10 ;i++){document.title =i;}}
}

xx.prototype.dd = function(){
alert("dd");
}

var a  = new  xx(100,"hello"),b =new  xx(0,"ttyp");
eval("a.aa =20");
a.bb();
b.dd();
alert(a.aa);

</TEXTAREA >   < BR >< INPUT  onclick =go()  type =button  value =go >< br >
< textarea  id =display  rows =12  cols =100 >
</ textarea >
</ BODY ></ HTML >

最后，本人原则上不赞成代码混淆加密，写本程序是出于研究目的，本程序本人原创，后续的代码压缩等功能陆续加上，程序中有任何问题请指正，任何转载请写明出处。