public static string  EncryptWithMD5(string source)
    {
        byte [] sor=Encoding.UTF8.GetBytes(source);
        MD5 md5=MD5.Create();
        byte [] result= md5.ComputeHash(sor);
        StringBuilder strbul=new StringBuilder(40);
        for(int i=0;i<result.Length;i++)
        {
            strbul.Append(result[i].ToString("x2"));//加密结果"x2"结果为32位,"x3"结果为48位,"x4"结果为64位

        }
        return strbul.ToString();
    }