/// <inheritdoc />
public override bool TryDecrypt(ReadOnlySpan <byte> key, ReadOnlySpan <byte> ciphertext, ReadOnlySpan <byte> nonce, Span <byte> plaintext, out int bytesWritten)
{
int keyLength = _encryptionAlgorithm.RequiredKeySizeInBits >> 4;
if (key.Length < keyLength)
{
ThrowHelper.ThrowArgumentOutOfRangeException_EncryptionKeyTooSmall(_encryptionAlgorithm, _encryptionAlgorithm.RequiredKeySizeInBits, _encryptionAlgorithm.RequiredKeySizeInBits >> 4);
}
if (ciphertext.Length == 0)
{
bytesWritten = 0;
return(true);
}
try
{
using var aes = Aes.Create();
aes.Key = key.ToArray();
aes.IV = nonce.ToArray();
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
using var decryptor = aes.CreateDecryptor();
bytesWritten = AesCbcHelper.Transform(decryptor, ciphertext, 0, ciphertext.Length, plaintext);
return(true);
}
catch (CryptographicException)
{
plaintext.Clear();
return(ThrowHelper.TryWriteError(out bytesWritten));
}
}
/// <inheritdoc />
public override bool TryDecrypt(ReadOnlySpan <byte> key, ReadOnlySpan <byte> ciphertext, ReadOnlySpan <byte> nonce, Span <byte> plaintext, out int bytesWritten)
{
if (key.IsEmpty)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.key);
}
if (ciphertext.IsEmpty)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.ciphertext);
}
if (nonce.IsEmpty)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.nonce);
}
int keyLength = _encryptionAlgorithm.RequiredKeySizeInBits >> 4;
if (key.Length < keyLength)
{
ThrowHelper.ThrowArgumentOutOfRangeException_EncryptionKeyTooSmall(_encryptionAlgorithm, _encryptionAlgorithm.RequiredKeySizeInBits, _encryptionAlgorithm.RequiredKeySizeInBits >> 4);
}
using var aes = Aes.Create();
aes.Key = key.ToArray();
aes.IV = nonce.ToArray();
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
using var decryptor = aes.CreateDecryptor();
bytesWritten = AesCbcHelper.Transform(decryptor, ciphertext, 0, ciphertext.Length, plaintext);
return(true);
}
/// <inheritdoc />
public override void Encrypt(
ReadOnlySpan <byte> key,
ReadOnlySpan <byte> plaintext,
ReadOnlySpan <byte> nonce,
Span <byte> ciphertext)
{
int keyLength = _encryptionAlgorithm.RequiredKeySizeInBytes >> 1;
if (key.Length < keyLength)
{
ThrowHelper.ThrowArgumentOutOfRangeException_EncryptionKeyTooSmall(_encryptionAlgorithm, _encryptionAlgorithm.RequiredKeySizeInBytes >> 1, key.Length << 3);
}
var aesKey = key.ToArray();
using Aes aes = CreateAes(aesKey);
try
{
aes.IV = nonce.ToArray();
using ICryptoTransform encryptor = aes.CreateEncryptor();
AesCbcHelper.Transform(encryptor, plaintext, 0, plaintext.Length, ciphertext);
}
catch
{
CryptographicOperations.ZeroMemory(ciphertext);
throw;
}
}
