/// <summary>
/// Encrypts a given password and returns the encrypted data
/// as a base64 string.
/// </summary>
/// <param name="plainText">An unencrypted string that needs
/// to be secured.</param>
/// <returns>A base64 encoded string that represents the encrypted
/// binary data.
/// </returns>
/// <remarks>This solution is not really secure as we are
/// keeping strings in memory. If runtime protection is essential,
/// <see cref="SecureString"/> should be used.</remarks>
/// <exception cref="ArgumentNullException">If <paramref name="plainText"/>
/// is a null reference.</exception>
public string Encrypt(string plainText)
{
if (plainText == null) throw new ArgumentNullException("plainText");
//encrypt data
var data = Encoding.Unicode.GetBytes(plainText);
byte[] encrypted = ProtectedData.Protect(data, null, Scope);
//return as base64 string
return Convert.ToBase64String(encrypted);
}
/// <summary>
/// Decrypts a given string.
/// </summary>
/// <param name="cipher">A base64 encoded string that was created
/// through the <see cref="Encrypt(string)"/> or
/// <see cref="Encrypt(SecureString)"/> extension methods.</param>
/// <returns>The decrypted string.</returns>
/// <remarks>Keep in mind that the decrypted string remains in memory
/// and makes your application vulnerable per se. If runtime protection
/// is essential, <see cref="SecureString"/> should be used.</remarks>
/// <exception cref="ArgumentNullException">If <paramref name="cipher"/>
/// is a null reference.</exception>
public string Decrypt(string cipher)
{
if (cipher == null) throw new ArgumentNullException("cipher");
//parse base64 string
byte[] data = Convert.FromBase64String(cipher);
//decrypt data
byte[] decrypted = ProtectedData.Unprotect(data, null, Scope);
return Encoding.Unicode.GetString(decrypted);
}