private static async Task <(MemoryStream output, IMS2SizeHeader size)> InternalGetEncryptionStreamAsync(Stream input, long inputSize, IMultiArray key, IMultiArray iv, long headerSize)
{
var cipher = CipherUtilities.GetCipher("AES/CTR/NoPadding");
var keyParam = ParameterUtilities.CreateKeyParameter("AES", key[inputSize]);
cipher.Init(true, new ParametersWithIV(keyParam, iv[inputSize]));
return(await InternalGetEncryptionStreamAsync(input, inputSize, cipher, headerSize).ConfigureAwait(false));
}
private static async Task <MemoryStream> InternalGetDecryptionStreamAsync(Stream input, IMS2SizeHeader size, IMultiArray key, IMultiArray iv, bool zlibCompressed)
{
var cipher = CipherUtilities.GetCipher("AES/CTR/NoPadding");
var keyParam = ParameterUtilities.CreateKeyParameter("AES", key[(uint)size.CompressedSize]);
cipher.Init(true, new ParametersWithIV(keyParam, iv[(uint)size.CompressedSize]));
return(await InternalGetDecryptionStreamAsync(input, size, cipher, zlibCompressed).ConfigureAwait(false));
}
public static async Task <(MemoryStream output, IMS2SizeHeader size)> GetEncryptionStreamAsync(Stream input, long inputSize, IMultiArray key, IMultiArray iv, bool zlibCompress)
{
if (zlibCompress)
{
using var ms = new MemoryStream();
using (var z = new ZlibStream(ms, CompressionMode.Compress, CompressionLevel.BestCompression, true))
{
byte[] inputBytes = new byte[inputSize];
int read = await input.ReadAsync(inputBytes, 0, (int)inputSize).ConfigureAwait(false);
if (read != inputSize)
{
throw new EndOfStreamException();
}
await z.WriteAsync(inputBytes, 0, (int)inputSize).ConfigureAwait(false);
}
ms.Position = 0;
return(await InternalGetEncryptionStreamAsync(ms, ms.Length, key, iv, inputSize).ConfigureAwait(false));
}
return(await InternalGetEncryptionStreamAsync(input, inputSize, key, iv, inputSize).ConfigureAwait(false));
}
public static async Task <MemoryStream> GetDecryptionStreamAsync(Stream input, IMS2SizeHeader size, IMultiArray key, IMultiArray iv, bool zlibCompressed)
{
using var ms = new MemoryStream();
byte[] encodedBytes = new byte[size.EncodedSize];
await input.ReadAsync(encodedBytes, 0, encodedBytes.Length).ConfigureAwait(false);
var encoder = new Base64Encoder();
encoder.Decode(encodedBytes, 0, encodedBytes.Length, ms);
if (ms.Length != size.CompressedSize)
{
throw new ArgumentException("Compressed bytes from input do not match with header size.", nameof(input));
}
ms.Position = 0;
return(await InternalGetDecryptionStreamAsync(ms, size, key, iv, zlibCompressed).ConfigureAwait(false));
}
