asp.net 对中文汉字的加密与解密代码

protected void Page_Load(object sender, EventArgs e) 
{ 
//加密算法 
string username = "我是陈建勇"; 
//MD5加密 - 得到32位加密数据,数据不好解密。过于复杂。 
username =FormsAuthentication.HashPasswordForStoringInConfigFile(username, "MD5"); 
//SHA1加密 - 得到40位加密数据,数据不好解密。过于复杂。 
string username1 = FormsAuthentication.HashPasswordForStoringInConfigFile(username, "SHA1"); 
Response.Write(username+"<br>"); 
Response.Write(username1+"<br>"); 
//解密算法 
//普通加密 
string s = "我是陈建勇"; 
string encodestr = ""; 
byte[] bytes = System.Text.Encoding.GetEncoding(0).GetBytes(s); 
try 
{ 
encodestr = Convert.ToBase64String(bytes); 
Response.Write("aa"); 
} 
catch 
{ 
encodestr = s; 
Response.Write("bb"); 
} 
Response.Write(encodestr+"<br>"); 
//普通解密 
string decodestr = ""; 
byte[] bytes1 = Convert.FromBase64String(encodestr); 
try 
{ 
decodestr = System.Text.Encoding.GetEncoding(0).GetString(bytes1); 
Response.Write("cc"); 
} 
catch 
{ 
Response.Write("dd"); 
decodestr = encodestr; 
} 
Response.Write(decodestr+"<br>"); 
//普通加密 
string myname = "陈建勇"; 
myname = System.Web.HttpUtility.UrlEncode(myname, System.Text.Encoding.UTF8); 
Response.Write(myname+"<br>"); 
//普通解密 
myname = System.Web.HttpUtility.UrlDecode(myname, System.Text.Encoding.UTF8); 
Response.Write(myname); 
}