js加密解密字符串可自定义密码因子

复制代码 代码如下:

  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

  <html xmlns="http://www.w3.org/1999/xhtml">

  <head>

  <meta http-equiv="Content-Type" content="text/html; charset=gb2312" />

  <title>字符串加密</title>

  </head>

  <body>

  <SCRIPT LANGUAGE="JavaScript">

  <!-- Begin

  function encrypt(str, pwd) {

  if(pwd == null || pwd.length <= 0) {

  alert("Please enter a password with which to encrypt the message.");

  return null;

  }

  var prand = "";

  for(var i=0; i<pwd.length; i++) {

  prand += pwd.charCodeAt(i).toString();

  }

  var sPos = Math.floor(prand.length / 5);

  var mult = parseInt(prand.charAt(sPos) + prand.charAt(sPos*2) + prand.charAt(sPos*3) + prand.charAt(sPos*4) + prand.charAt(sPos*5));

  var incr = Math.ceil(pwd.length / 2);

  var modu = Math.pow(2, 31) - 1;

  if(mult < 2) {

  alert("Algorithm cannot find a suitable hash. Please choose a different password. \nPossible considerations are to choose a more complex or longer password.");

  return null;

  }

  var salt = Math.round(Math.random() * 1000000000) % 100000000;

  prand += salt;

  while(prand.length > 10) {

  prand = (parseInt(prand.substring(0, 10)) + parseInt(prand.substring(10, prand.length))).toString();

  }

  prand = (mult * prand + incr) % modu;

  var enc_chr = "";

  var enc_str = "";

  for(var i=0; i<str.length; i++) {

  enc_chr = parseInt(str.charCodeAt(i) ^ Math.floor((prand / modu) * 255));

  if(enc_chr < 16) {

  enc_str += "0" + enc_chr.toString(16);

  } else enc_str += enc_chr.toString(16);

  prand = (mult * prand + incr) % modu;

  }

  salt = salt.toString(16);

  while(salt.length < 8)salt = "0" + salt;

  enc_str += salt;

  return enc_str;

  }

  function decrypt(str, pwd) {

  if(str == null || str.length < 8) {

  alert("A salt value could not be extracted from the encrypted message because it's length is too short. The message cannot be decrypted.");

  return;

  }

  if(pwd == null || pwd.length <= 0) {

  alert("Please enter a password with which to decrypt the message.");

  return;

  }

  var prand = "";

  for(var i=0; i<pwd.length; i++) {

  prand += pwd.charCodeAt(i).toString();

  }

  var sPos = Math.floor(prand.length / 5);

  var mult = parseInt(prand.charAt(sPos) + prand.charAt(sPos*2) + prand.charAt(sPos*3) + prand.charAt(sPos*4) + prand.charAt(sPos*5));

  var incr = Math.round(pwd.length / 2);

  var modu = Math.pow(2, 31) - 1;

  var salt = parseInt(str.substring(str.length - 8, str.length), 16);

  str = str.substring(0, str.length - 8);

  prand += salt;

  while(prand.length > 10) {

  prand = (parseInt(prand.substring(0, 10)) + parseInt(prand.substring(10, prand.length))).toString();

  }

  prand = (mult * prand + incr) % modu;

  var enc_chr = "";

  var enc_str = "";

  for(var i=0; i<str.length; i+=2) {

  enc_chr = parseInt(parseInt(str.substring(i, i+2), 16) ^ Math.floor((prand / modu) * 255));

  enc_str += String.fromCharCode(enc_chr);

  prand = (mult * prand + incr) % modu;

  }

  return enc_str;

  }

  // End -->

  </script>

  <form name="box"><center>

  <table cellpadding=0 cellspacing=0 border=0><tr><td colspan=3>

  <textarea cols=40 rows=5 wrap=virtual name=ipt>Welcome to baidu.com</textarea>

  </td></tr>

  <tr height=50><td valign="top">

  <input type="button" onclick="document.box.opt.value= encrypt(document.box.ipt.value, document.box.pwd.value);" value="加密">

  </td><td align="center" valign="center">

  <input type="text" name="pwd" value="password">

  </td><td align="right" valign="bottom">

  <input type="button" onclick="document.box.ipt.value= decrypt(document.box.opt.value, document.box.pwd.value);" value="解密">

  </td></tr>

  <tr><td colspan=3>

  <textarea cols=40 rows=5 wrap=virtual name=opt></textarea>

  </td></tr></table>

  </center>

  </form>

  </body>

  </html>

  代码copy之后直接打开即可