ASP.NET加密，解密算法，MD5/DES

#region MD5算法（md5不可解密，加密后判断是否相等）

public string md5(string str, int code)

{

if (code == 16) //16位MD5加密（取32位加密的9~25字符）

{

return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower().Substring(8, 16);

}

if (code == 32) //32位加密

{

return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower();

}

return "00000000000000000000000000000000";

}

#endregion

//加密

public static string EnCode(string s)

{

string encodestr = "";

byte[] bytes = System.Text.Encoding.GetEncoding(0).GetBytes(s);

try

{

encodestr = Convert.ToBase64String(bytes);

}

catch

{

encodestr = s;

}

return encodestr;

}

//解密

public static string DeCode(string s)

{

string decodestr = "";

byte[] bytes = Convert.FromBase64String(s);

try

{

decodestr = System.Text.Encoding.GetEncoding(0).GetString(bytes);

}

catch

{

decodestr = s;

}

return decodestr;

}