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Improve AES-CTR performance

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This commit is contained in:
Alex Barney 2018-06-29 18:49:53 -05:00
parent 16405583ce
commit d24028f34d
3 changed files with 32 additions and 87 deletions
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26
hactoolnet/Program.cs
View file

@ -1,4 +1,5 @@
using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using libhac;
@ -35,12 +36,17 @@ namespace hactoolnet
var title = sdfs.Titles[0x0100E95004038000];
var nca = title.ProgramNca;
var romfsStream = nca.OpenSection(1, false);
var romfs = new Romfs(romfsStream);
var file = romfs.OpenFile("/stream/voice/us/127/127390101.nop");
using (var output = new FileStream("127390101.nop", FileMode.Create))
var romfs = new Romfs(romfsStream);
var file = romfs.OpenFile("/bf2.ard");
using (var progress = new ProgressBar())
using (var output = new FileStream("bf2.ard", FileMode.Create))
{
file.CopyTo(output);
var watch = Stopwatch.StartNew();
file.CopyStream(output, file.Length / 100, progress);
watch.Stop();
progress.LogMessage(watch.Elapsed.TotalSeconds.ToString());
}
}
@ -53,11 +59,15 @@ namespace hactoolnet
var romfsStream = nca.OpenSection(1, false);
var romfs = new Romfs(romfsStream);
var bfstm = romfs.OpenFile("/Sound/Resource/Stream/BGM_Castle.bfstm");
var bfstm = romfs.OpenFile("/Sound/Resource/Stream/Demo149_1_SoundTrack.bfstm");
using (var output = new FileStream("BGM_Castle.bfstm", FileMode.Create))
using (var progress = new ProgressBar())
using (var output = new FileStream("Demo149_1_SoundTrack.bfstm", FileMode.Create))
{
bfstm.CopyTo(output);
var watch = Stopwatch.StartNew();
bfstm.CopyStream(output, bfstm.Length, progress);
watch.Stop();
progress.LogMessage(watch.Elapsed.TotalSeconds.ToString());
}
}
}
@ -66,7 +76,7 @@ namespace hactoolnet
{
var sdfs = LoadSdFs(args);
var nca = sdfs.Ncas["8EE79C7AB0F16737BC50F049DFDBB595"];
var romfsStream =nca.OpenSection(1, false);
var romfsStream = nca.OpenSection(1, false);
var romfs = new Romfs(romfsStream);
}

91
libhac/Aes128CounterMode.cs
View file

@ -21,87 +21,39 @@
// THE SOFTWARE.
using System;
using System.Collections.Generic;
using System.Security.Cryptography;
namespace libhac
{
public class Aes128CounterMode : SymmetricAlgorithm
{
private readonly byte[] _counter = new byte[0x10];
private readonly AesManaged _aes;
public Aes128CounterMode()
{
_aes = new AesManaged
{
Mode = CipherMode.ECB,
Padding = PaddingMode.None
};
}
public override ICryptoTransform CreateEncryptor(byte[] rgbKey, byte[] ignoredParameter)
{
return new CounterModeCryptoTransform(_aes, rgbKey, _counter);
}
public override ICryptoTransform CreateDecryptor(byte[] rgbKey, byte[] ignoredParameter)
{
return new CounterModeCryptoTransform(_aes, rgbKey, _counter);
}
public override void GenerateKey()
{
_aes.GenerateKey();
}
public override void GenerateIV()
{
// IV not needed in Counter Mode
}
}
public class CounterModeCryptoTransform : ICryptoTransform
public class CounterModeCryptoTransform
{
private const int BlockSize = 128;
private const int BlockSizeBytes = BlockSize / 8;
private readonly byte[] _counter;
private readonly byte[] _counterEnc = new byte[0x10];
private readonly ICryptoTransform _counterEncryptor;
private readonly Queue<byte> _xorMask = new Queue<byte>();
private readonly SymmetricAlgorithm _symmetricAlgorithm;
public CounterModeCryptoTransform(SymmetricAlgorithm symmetricAlgorithm, byte[] key, byte[] counter)
{
if (symmetricAlgorithm == null) throw new ArgumentNullException(nameof(symmetricAlgorithm));
if (key == null) throw new ArgumentNullException(nameof(key));
if (counter == null) throw new ArgumentNullException(nameof(counter));
if (counter.Length != symmetricAlgorithm.BlockSize / 8)
if (counter.Length != BlockSizeBytes)
throw new ArgumentException(String.Format("Counter size must be same as block size (actual: {0}, expected: {1})",
counter.Length, symmetricAlgorithm.BlockSize / 8));
counter.Length, BlockSizeBytes));
_symmetricAlgorithm = symmetricAlgorithm;
_counter = counter;
var zeroIv = new byte[_symmetricAlgorithm.BlockSize / 8];
_counterEncryptor = symmetricAlgorithm.CreateEncryptor(key, zeroIv);
_counterEncryptor = symmetricAlgorithm.CreateEncryptor(key, new byte[BlockSize / 8]);
}
public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount)
public int TransformBlock(byte[] inputBuffer, int inputOffset, byte[] outputBuffer, int outputOffset)
{
var output = new byte[inputCount];
TransformBlock(inputBuffer, inputOffset, inputCount, output, 0);
return output;
}
public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
{
for (var i = 0; i < inputCount; i++)
EncryptCounterThenIncrement();
for (int i = 0; i < 16; i++)
{
if (NeedMoreXorMaskBytes()) EncryptCounterThenIncrement();
var mask = _xorMask.Dequeue();
outputBuffer[outputOffset + i] = (byte)(inputBuffer[inputOffset + i] ^ mask);
outputBuffer[outputOffset + i] = (byte)(inputBuffer[inputOffset + i] ^ _counterEnc[i]);
}
return inputCount;
return 16;
}
public void UpdateCounter(long offset)
@ -114,22 +66,10 @@ namespace libhac
}
}
private bool NeedMoreXorMaskBytes()
{
return _xorMask.Count == 0;
}
private void EncryptCounterThenIncrement()
{
var counterModeBlock = new byte[_symmetricAlgorithm.BlockSize / 8];
_counterEncryptor.TransformBlock(_counter, 0, _counter.Length, counterModeBlock, 0);
_counterEncryptor.TransformBlock(_counter, 0, _counter.Length, _counterEnc, 0);
IncrementCounter();
foreach (var b in counterModeBlock)
{
_xorMask.Enqueue(b);
}
}
private void IncrementCounter()
@ -141,11 +81,6 @@ namespace libhac
}
}
public int InputBlockSize => _symmetricAlgorithm.BlockSize / 8;
public int OutputBlockSize => _symmetricAlgorithm.BlockSize / 8;
public bool CanTransformMultipleBlocks => true;
public bool CanReuseTransform => false;
public void Dispose()
{
}

2
libhac/AesCtrStream.cs
View file

@ -166,7 +166,7 @@ namespace libhac
_decryptor = CreateDecryptor();
//decrypt the sector
var retV = _decryptor.TransformBlock(_tempBuffer, 0, ret, buffer, offset);
var retV = _decryptor.TransformBlock(_tempBuffer, 0, buffer, offset);
//Console.WriteLine("Decrypting sector {0} == {1} bytes", currentSector, retV);