private static ICryptoTransform CreateCryptoTransform(SymmetricEncryptionSettings settings, Stream stream)
{
Check.NotNull(settings, nameof(settings));
Check.NotNull(stream, nameof(stream));
using var algorithm = SymmetricAlgorithmFactory.CreateSymmetricAlgorithm(settings);
if (settings.InitializationVector == null)
{
// Read the IV prepended to the message
byte[] buffer = new byte[algorithm.IV.Length];
int totalReadCount = 0;
while (totalReadCount < algorithm.IV.Length)
{
int readCount = stream.Read(buffer, totalReadCount, algorithm.IV.Length - totalReadCount);
if (readCount == 0)
{
break;
}
totalReadCount = totalReadCount + readCount;
}
algorithm.IV = buffer;
}
return(algorithm.CreateDecryptor());
}
private ICryptoTransform CreateCryptoTransform(SymmetricEncryptionSettings settings)
{
using var algorithm = SymmetricAlgorithmFactory.CreateSymmetricAlgorithm(settings);
if (settings.InitializationVector == null)
{
_prefixBuffer = algorithm.IV;
}
return(algorithm.CreateEncryptor());
}
private static ICryptoTransform CreateCryptoTransform(
SymmetricDecryptionSettings settings,
Stream stream,
string?keyIdentifier)
{
Check.NotNull(settings, nameof(settings));
Check.NotNull(stream, nameof(stream));
byte[]? encryptionKey = settings.KeyProvider != null
? settings.KeyProvider(keyIdentifier)
: settings.Key;
using var algorithm =
SymmetricAlgorithmFactory.CreateSymmetricAlgorithm(settings, encryptionKey);
if (settings.InitializationVector != null)
{
return(algorithm.CreateDecryptor());
}
// Read the IV prepended to the message
byte[] buffer = new byte[algorithm.IV.Length];
var totalReadCount = 0;
while (totalReadCount < algorithm.IV.Length)
{
int readCount = stream.Read(buffer, totalReadCount, algorithm.IV.Length - totalReadCount);
if (readCount == 0)
{
break;
}
totalReadCount += readCount;
}
algorithm.IV = buffer;
return(algorithm.CreateDecryptor());
}
