JS到PHP使用RSA算法进行加密通讯

我们平时做用户登录表单提交，用户名密码都是明文直接POST到后端，这样很容易被别人从监听到。

在js上做rsa，感觉jsencrypt这个是封装的比较好的，但用起来还是遇到了些坑，所以踩进代码里填填坑～

项目在这里 https://github.com/travist/jsencrypt

关于jsencrypt和RSA我就不多介绍了，直接上代码

因为jsencrypt与最新的PHP不兼容所以折腾了好久，在js上做了些改动

可直接下载修改过的js：http://pan.baidu.com/s/1qYu0FA8

1，编辑jsencrypt.js，添加3个方法:

 function RSAEncryptLong(text) {
   var length = ((this.n.bitLength()+7)>>3) - 11;
   if (length <= 0) return false;
   var ret = "";
   var i = 0;
   while(i + length < text.length) {
     ret += this._short_encrypt(text.substring(i,i+length));
     i += length;
   }
   ret += this._short_encrypt(text.substring(i,text.length));
   return ret;
 }
 
 /**
    * base64编码
    * @param {Object} str
    */
   function base64encode(str){
     var out, i, len;
     var c1, c2, c3;
     len = str.length;
     i = 0;
     out = "";
     while (i < len) {
       c1 = str.charCodeAt(i++) & 0xff;
       if (i == len) {
         out += base64EncodeChars.charAt(c1 >> 2);
         out += base64EncodeChars.charAt((c1 & 0x3) << 4);
         out += "==";
         break;
       }
       c2 = str.charCodeAt(i++);
       if (i == len) {
         out += base64EncodeChars.charAt(c1 >> 2);
         out += base64EncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));
         out += base64EncodeChars.charAt((c2 & 0xF) << 2);
         out += "=";
         break;
       }
       c3 = str.charCodeAt(i++);
       out += base64EncodeChars.charAt(c1 >> 2);
       out += base64EncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));
       out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6));
       out += base64EncodeChars.charAt(c3 & 0x3F);
     }
     return out;
   }
 
   /**
    * base64解码
    * @param {Object} str
    */
   function base64decode(str){
     var c1, c2, c3, c4;
     var i, len, out;
     len = str.length;
     i = 0;
     out = "";
     while (i < len) {
       /* c1 */
       do {
         c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
       }
       while (i < len && c1 == -1);
       if (c1 == -1)
         break;
       /* c2 */
       do {
         c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
       }
       while (i < len && c2 == -1);
       if (c2 == -1)
         break;
       out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));
       /* c3 */
       do {
         c3 = str.charCodeAt(i++) & 0xff;
         if (c3 == 61)
           return out;
         c3 = base64DecodeChars[c3];
       }
       while (i < len && c3 == -1);
       if (c3 == -1)
         break;
       out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));
       /* c4 */
       do {
         c4 = str.charCodeAt(i++) & 0xff;
         if (c4 == 61)
           return out;
         c4 = base64DecodeChars[c4];
       }
       while (i < len && c4 == -1);
       if (c4 == -1)
         break;
       out += String.fromCharCode(((c3 & 0x03) << 6) | c4);
     }
     return out;
   }

2，找到这一行

RSAKey.prototype.encrypt = RSAEncrypt;

修改为：

RSAKey.prototype.encrypt = RSAEncryptLong;
RSAKey.prototype._short_encrypt = RSAEncrypt;

3，找到这一行代码

JSEncrypt.prototype.encrypt = function (string) {
  // Return the encrypted string.
  try {
    return hex2b64(this.getKey().encrypt(string));
  }

修改为：

JSEncrypt.prototype.encrypt = function (string) {
  // Return the encrypted string.
  try {
    return base64encode(this.getKey().encrypt(string));
  }

4，页面js加密代码

 <script type="text/javascript" src="jsencrypt.js"></script>
 <script>
 function encrypt(msg) {
     var rsa = new JSEncrypt();
     rsa.setPublic('

-----BEGIN PUBLIC KEY-----MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC6LHB0pVFfBSUkTtzQVXvX4ohF3M0jb/7JdTs3GJccf+VhYjIIdOmFFGrJFXAI459VbTuobG/yoCN5OOWs7NrCZvFQ3gS9u7RU2Mf7vK3So+hP56ijWMMzVkmBwyKF9U6NQ4Q4NhUMIpe/8HA87eps1n2emxEbxrNanvSQi3c1VwIDAQAB-----END PUBLIC KEY-----

', '10001'); 
  return rsa.encrypt(msg); 
 } 
 </script>

5，PHP解密代码

 require_once('Crypt/RSA.php');
 define("KEY_PRIVATE", "

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

"); 
 
 function decrypt(msg) { 
  $rsa = new Crypt_RSA(); 
  $rsa->setEncryptionMode(CRYPT_RSA_ENCRYPTION_PKCS1); 
  $rsa->loadKey(KEY_PRIVATE, CRYPT_RSA_PRIVATE_FORMAT_PKCS1); 
  $s = new Math_BigInteger(base64_decode(msg), 16); 
  retrun $rsa->decrypt($s->toBytes()); 
 }

在线生成RSA秘钥对：http://travistidwell.com/jsencrypt/demo/

最后 我希望这个解决方案能帮助你们中的一些人。如果我的文章有什么问题，请随时联系帮助我纠正它。

参考：

http://travistidwell.com/jsencrypt/

http://travistidwell.com/jsencrypt/demo/

http://bestmike007.com/2011/08/secure-data-transmission-between-pure-php-and-javascript-using-rsa/