public override EncryptResult Encrypt(EncryptOptions options, CancellationToken cancellationToken = default)
{
Argument.AssertNotNull(options, nameof(options));
ThrowIfTimeInvalid();
EncryptionAlgorithm algorithm = options.Algorithm;
if (algorithm.GetAesCbcEncryptionAlgorithm() is AesCbc aesCbc)
{
// Make sure the IV is initialized.
options.Initialize();
using ICryptoTransform encryptor = aesCbc.CreateEncryptor(KeyMaterial.K, options.Iv);
byte[] plaintext = options.Plaintext;
byte[] ciphertext = encryptor.TransformFinalBlock(plaintext, 0, plaintext.Length);
return(new EncryptResult
{
Algorithm = algorithm,
KeyId = KeyMaterial.Id,
Ciphertext = ciphertext,
Iv = options.Iv,
});
}
else if (algorithm.IsAesGcm() && AesGcmProxy.TryCreate(KeyMaterial.K, out AesGcmProxy aesGcm))
{
using (aesGcm)
{
byte[] plaintext = options.Plaintext;
byte[] ciphertext = new byte[plaintext.Length];
byte[] tag = new byte[AesGcmProxy.NonceByteSize];
// Generate an nonce only for local AES-GCM; Managed HSM will do it service-side and err if serialized.
byte[] iv = Crypto.GenerateIv(AesGcmProxy.NonceByteSize);
aesGcm.Encrypt(iv, plaintext, ciphertext, tag, options.AdditionalAuthenticatedData);
return(new EncryptResult
{
Algorithm = algorithm,
KeyId = KeyMaterial.Id,
Ciphertext = ciphertext,
Iv = iv,
AuthenticationTag = tag,
AdditionalAuthenticatedData = options.AdditionalAuthenticatedData,
});
}
}
else
{
KeysEventSource.Singleton.AlgorithmNotSupported(nameof(Encrypt), algorithm);
return(null);
}
}
public override DecryptResult Decrypt(DecryptOptions options, CancellationToken cancellationToken = default)
{
Argument.AssertNotNull(options, nameof(options));
ThrowIfTimeInvalid();
EncryptionAlgorithm algorithm = options.Algorithm;
if (algorithm.GetAesCbcEncryptionAlgorithm() is AesCbc aesCbc)
{
using ICryptoTransform decryptor = aesCbc.CreateDecryptor(KeyMaterial.K, options.Iv);
byte[] ciphertext = options.Ciphertext;
byte[] plaintext = decryptor.TransformFinalBlock(ciphertext, 0, ciphertext.Length);
return(new DecryptResult
{
Algorithm = algorithm,
KeyId = KeyMaterial.Id,
Plaintext = plaintext,
});
}
else if (algorithm.IsAesGcm() && AesGcmProxy.TryCreate(KeyMaterial.K, out AesGcmProxy aesGcm))
{
using (aesGcm)
{
byte[] ciphertext = options.Ciphertext;
byte[] plaintext = new byte[ciphertext.Length];
aesGcm.Decrypt(options.Iv, ciphertext, options.AuthenticationTag, plaintext, options.AdditionalAuthenticatedData);
return(new DecryptResult
{
Algorithm = algorithm,
KeyId = KeyMaterial.Id,
Plaintext = plaintext,
});
}
}
else
{
KeysEventSource.Singleton.AlgorithmNotSupported(nameof(Decrypt), algorithm);
return(null);
}
}
public static bool TryCreate(byte[] key, out AesGcmProxy proxy)
{
Type t = typeof(Aes).Assembly.GetType("System.Security.Cryptography.AesGcm", false);
if (t != null)
{
try
{
object aes = Activator.CreateInstance(t, key);
proxy = new AesGcmProxy(aes);
return(true);
}
catch
{
}
}
proxy = null;
return(false);
}
