public void DecryptsToOriginalPlainText()
{
byte[] plaintextBytes = Encoding.UTF8.GetBytes("This is a test! It needs to be 128 characters long at least. This is a test! It needs to be 128 characters long at least. This is a test! It needs to be 128 characters long at least. This is a test! It needs to be 128 characters long at least. This is a test! It needs to be 128 characters long at least. This is a test! It needs to be 128 characters long at least. This is a test! It needs to be 128 characters long at least. This is a test! It needs to be 128 characters long at least.");
byte[] decryptedBytes;
using (SymmetricAlgorithm algorithm = new AesManaged())
{
byte[] wrongDecryptionKey = algorithm.Key;
algorithm.GenerateKey();
byte[] encryptionKey = algorithm.Key;
Assert.AreNotEqual(encryptionKey, wrongDecryptionKey);
byte[] ciphertextBytes, iv;
using (Encryptor encryptor = algorithm.CreateEncryptor(encryptionKey, out iv))
{
Assert.AreEqual(encryptionKey, encryptor.Algorithm.Key);
Assert.AreEqual(iv, encryptor.Algorithm.IV);
ciphertextBytes = encryptor.Encrypt(plaintextBytes);
}
using (Decryptor decryptor = new Decryptor(algorithm, encryptionKey, iv, Encryption.DefaultOptions))
{
Assert.AreEqual(encryptionKey, decryptor.Algorithm.Key);
Assert.AreEqual(iv, decryptor.Algorithm.IV);
decryptedBytes = decryptor.Decrypt(ciphertextBytes);
}
}
Assert.AreEqual(plaintextBytes, decryptedBytes);
}
public void CausesDecryptionToReturnNonsense()
{
byte[] plaintextBytes = Encoding.UTF8.GetBytes("This is a test!");
byte[] decryptedBytes, decryptedBytesFromWrongKey = null;
using (SymmetricAlgorithm algorithm = new AesManaged())
{
byte[] wrongDecryptionKey = algorithm.Key;
algorithm.GenerateKey();
byte[] encryptionKey = algorithm.Key;
Assert.AreNotEqual(encryptionKey, wrongDecryptionKey);
byte[] ciphertextBytes, iv;
using (Encryptor encryptor = algorithm.CreateEncryptor(encryptionKey, out iv))
{
Assert.AreEqual(encryptionKey, encryptor.Algorithm.Key);
Assert.AreEqual(iv, encryptor.Algorithm.IV);
ciphertextBytes = encryptor.Encrypt(plaintextBytes);
}
using (Decryptor decryptorWithWrongKey = new Decryptor(algorithm, wrongDecryptionKey, iv, Encryption.DefaultOptions))
{
Assert.AreEqual(wrongDecryptionKey, decryptorWithWrongKey.Algorithm.Key);
Assert.AreEqual(iv, decryptorWithWrongKey.Algorithm.IV);
try
{
decryptedBytesFromWrongKey = decryptorWithWrongKey.Decrypt(ciphertextBytes);
}
catch (CryptographicException e)
{
// "Padding is invalid and cannot be removed."
Assert.IsNull(decryptedBytesFromWrongKey);
Console.WriteLine(e.Message);
}
}
using (Decryptor decryptor = new Decryptor(algorithm, encryptionKey, iv, Encryption.DefaultOptions))
{
Assert.AreEqual(encryptionKey, decryptor.Algorithm.Key);
Assert.AreEqual(iv, decryptor.Algorithm.IV);
decryptedBytes = decryptor.Decrypt(ciphertextBytes);
}
}
Assert.AreNotEqual(decryptedBytes, decryptedBytesFromWrongKey);
Assert.AreEqual(plaintextBytes, decryptedBytes);
}
public static byte[] Decrypt <T>(
this byte[] encryptedBytes,
[NotNull] byte[] key,
[NotNull] byte[] iv,
EncryptionOptions options = Encryption.DefaultOptions)
where T : SymmetricAlgorithm
{
Contract.Requires <ArgumentNullException>(key != null);
Contract.Requires <ArgumentNullException>(iv != null);
byte[] decryptedBytes;
using (Decryptor <T> decryptor = new Decryptor <T>(key, iv, options))
{
decryptedBytes = decryptor.Decrypt(encryptedBytes);
}
return(decryptedBytes);
}
