greenshot/GreenshotPlugin/Core/EncryptionHelper.cs

/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2012  Thomas Braun, Jens Klingen, Robin Krom
 * 
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on Sourceforge: http://sourceforge.net/projects/greenshot/
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace GreenshotPlugin.Core {
	public static class EncryptionHelper {
		private static readonly log4net.ILog LOG = log4net.LogManager.GetLogger("EncryptionHelper");
		private const string RGBIV = "dlgjowejgogkklwj";
		private const string KEY = "lsjvkwhvwujkagfauguwcsjgu2wueuff";

		/// <summary>
		/// A simply rijndael aes encryption, can be used to store passwords
		/// </summary>
		/// <param name="ClearText">the string to call upon</param>
		/// <returns>an encryped string in base64 form</returns>
		public static string Encrypt(this string ClearText) {
			string returnValue = ClearText;
			try {
				byte[] clearTextBytes = Encoding.ASCII.GetBytes(ClearText);
				SymmetricAlgorithm rijn = SymmetricAlgorithm.Create();
	
				using (MemoryStream ms = new MemoryStream()) {
					byte[] rgbIV = Encoding.ASCII.GetBytes(RGBIV);
					byte[] key = Encoding.ASCII.GetBytes(KEY);
					CryptoStream cs = new CryptoStream(ms, rijn.CreateEncryptor(key, rgbIV), CryptoStreamMode.Write);
	
					cs.Write(clearTextBytes, 0, clearTextBytes.Length);
	
					cs.Close();
					returnValue = Convert.ToBase64String(ms.ToArray());
				}
			} catch (Exception ex) {
				LOG.ErrorFormat("Error encrypting, error: ", ex.Message);
			}
			return returnValue;
		}

		/// <summary>
		/// A simply rijndael aes decryption, can be used to store passwords
		/// </summary>
		/// <param name="EncryptedText">a base64 encoded rijndael encrypted string</param>
		/// <returns>Decrypeted text</returns>
		public static string Decrypt(this string EncryptedText) {
			string returnValue = EncryptedText;
			try {
				byte[] encryptedTextBytes = Convert.FromBase64String(EncryptedText);
				using (MemoryStream ms = new MemoryStream()) {
					SymmetricAlgorithm rijn = SymmetricAlgorithm.Create();
	
	
					byte[] rgbIV = Encoding.ASCII.GetBytes(RGBIV);
					byte[] key = Encoding.ASCII.GetBytes(KEY);
	
					CryptoStream cs = new CryptoStream(ms, rijn.CreateDecryptor(key, rgbIV),
					CryptoStreamMode.Write);
	
					cs.Write(encryptedTextBytes, 0, encryptedTextBytes.Length);
	
					cs.Close();
					returnValue = Encoding.ASCII.GetString(ms.ToArray());
				}
			} catch (Exception ex) {
				LOG.ErrorFormat("Error decrypting {0}, error: ", EncryptedText, ex.Message);
			}

			return returnValue;
		}
	}
}