public static string Decrypt(string source)
{
byte[] buff = null;
if (source.Length > 2 && source[0] == '1' && source[1] == '+')
{
buff = new byte[(source.Length - 2) / 2];
string key = ClientCommunication.GetWindowsUserName();
if (key == String.Empty)
{
return(String.Empty);
}
int kidx = 0;
for (int i = 2; i < source.Length; i += 2)
{
byte c;
try
{
c = Convert.ToByte(source.Substring(i, 2), 16);
}
catch
{
continue;
}
buff[(i - 2) / 2] = (byte)(c ^ ((byte)key[kidx++]));
if (kidx >= key.Length)
{
kidx = 0;
}
}
}
else
{
byte key = (byte)(source.Length / 2);
buff = new byte[key];
for (int i = 0; i < source.Length; i += 2)
{
byte c;
try
{
c = Convert.ToByte(source.Substring(i, 2), 16);
}
catch
{
continue;
}
buff[i / 2] = (byte)(c ^ key++);
}
}
return(ASCIIEncoding.ASCII.GetString(buff));
}
public static string Encrypt(string source)
{
byte[] buff = ASCIIEncoding.ASCII.GetBytes(source);
int kidx = 0;
string key = ClientCommunication.GetWindowsUserName();
if (key == String.Empty)
{
return(String.Empty);
}
StringBuilder sb = new StringBuilder(source.Length * 2 + 2);
sb.Append("1+");
for (int i = 0; i < buff.Length; i++)
{
sb.AppendFormat("{0:X2}", (byte)(buff[i] ^ ((byte)key[kidx++])));
if (kidx >= key.Length)
{
kidx = 0;
}
}
return(sb.ToString());
}
