public CipherMessage EncryptMessage(string text)
{
// Convert string to a byte array
CipherMessage message = new CipherMessage();
byte[] plainBytes = Encoding.Unicode.GetBytes(text.ToCharArray());
// A new key and iv are generated for every message
rc2.GenerateKey();
rc2.GenerateIV();
// The rc2 initialization doesnt need to be encrypted, but will
// be used in conjunction with the key to decrypt the message.
message.rc2IV = rc2.IV;
try
{
// Encrypt the RC2 key using RSA encryption
message.rc2Key = rsa.Encrypt(rc2.Key, false);
}
catch (CryptographicException e)
{
// The High Encryption Pack is required to run this sample
// because we are using a 128-bit key. See the readme for
// additional information.
Console.WriteLine("Encryption Failed. Ensure that the" +
" High Encryption Pack is installed.");
Console.WriteLine("Error Message: " + e.Message);
Environment.Exit(0);
}
// Encrypt the Text Message using RC2 (Symmetric algorithm)
ICryptoTransform sse = rc2.CreateEncryptor();
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, sse, CryptoStreamMode.Write);
try
{
cs.Write(plainBytes, 0, plainBytes.Length);
cs.FlushFinalBlock();
message.cipherBytes = ms.ToArray();
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{
ms.Close();
cs.Close();
}
return(message);
} // method EncryptMessage
} // method EncryptMessage
public void DecryptMessage(CipherMessage message)
{
// Get the RC2 Key and Initialization Vector
rc2.IV = message.rc2IV;
try
{
// Try decrypting the rc2 key
rc2.Key = rsa.Decrypt(message.rc2Key, false);
}
catch (CryptographicException e)
{
Console.WriteLine("Decryption Failed: " + e.Message);
return;
}
ICryptoTransform ssd = rc2.CreateDecryptor();
// Put the encrypted message in a memorystream
MemoryStream ms = new MemoryStream(message.cipherBytes);
// the CryptoStream will read cipher text from the MemoryStream
CryptoStream cs = new CryptoStream(ms, ssd, CryptoStreamMode.Read);
byte[] initialText = new Byte[message.cipherBytes.Length];
try
{
// Decrypt the message and store in byte array
cs.Read(initialText, 0, initialText.Length);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{
ms.Close();
cs.Close();
}
// Display the message received
Console.WriteLine(name + " received the following message:");
Console.WriteLine(" " + Encoding.Unicode.GetString(initialText));
} // method DecryptMessage
