一种简易的数字加密方法

这是我无意中写的一个简易的加密方法，现在放出来，其实是因为没有用了，不过是提醒自己，数字要加密而已，所以将这个放了出来，大家也可以看看，有好的加密方法的朋友，可以交流一下

public function NumberConvert(){}public static function getNum(str:String):String{if(str==null)return null;var _num:String="";for(var i:int=0;i<str.length;i++){var tmp:String= str.charAt(i);_num=_num+strToNum(tmp);}return _num;}public static function getString(num:String):String{if(num==null) return null;var _str:String="";for(var i:int=0;i<num.length;i++){var tmp:String=num.charAt(i);_str=_str+numToStr(tmp);}return _str;}private static function numToStr(tmp :String):String{switch (tmp){case "0":return "I";break;case "1":return "O";break;case "2":return "x";break;case "3":return "l";break;case "4":return "C";break;case "5":return "Z";break;case "6":return "D";break;case "7":return "F";break;case "8":return "S";break;case "9":return "T";break;case ".":return "^";break;default :return "error";break;}}private static function strToNum(str:String):String{switch (str){case "I":return "0";break;case "O":return "1";break;case "x":return "2";break;case "l":return "3";break;case "C":return "4";break;case "Z":return "5";break;case "D":return "6";break;case "F":return "7";break;case "S":return "8";break;case "T":return "9";break;case "^":return ".";break;default :return "error";break;}}