ClassiCube/Launcher2/Secure.cs

using System;
using System.Security.Cryptography;

namespace Launcher2 {
	
	public static class Secure {
		
		public static string Encode( string decoded, string key ) {
			if( String.IsNullOrEmpty( decoded ) || String.IsNullOrEmpty( key ) ) return "";
			
			byte[] data = new byte[decoded.Length];
			for( int i = 0; i < decoded.Length; i++ )
				data[i] = (byte)decoded[i];
			
			try {
				byte[] v2 = ProtectedData.Protect( data, null, DataProtectionScope.CurrentUser );
				return Convert.ToBase64String( v2 );
			} catch {
				// XORs data. *NOT* very secure, only designed to prevent reading from options.txt.
				for( int i = 0; i < data.Length; i++ )
					data[i] = (byte)(data[i] ^ key[i % key.Length] ^ 0x43);
				return Convert.ToBase64String( data );
			}
		}
		
		public static string Decode( string encoded, string key ) {
			if( String.IsNullOrEmpty( encoded ) || String.IsNullOrEmpty( key ) ) return "";
			
			byte[] data;
			try {
				data = Convert.FromBase64String( encoded );
			} catch( FormatException ) {
				return "";
			}
			
			try {
				data = ProtectedData.Unprotect( data, null, DataProtectionScope.CurrentUser );
				char[] c = new char[data.Length];
				for( int i = 0; i < c.Length; i++ )
					c[i] = (char)data[i];
				return new String( c );
			} catch {
				if( encoded.Length > 64 || data.Length > 64 ) return "";
				
				char[] c = new char[data.Length];
				for( int i = 0; i < c.Length; i++ )
					c[i] = (char)(data[i] ^ key[i % key.Length] ^ 0x43);
				return new String( c );
			}
		}
	}
}