public static void Crypt(HcaInfo hca, byte[][] audio, CriHcaKey key, bool doDecrypt)
{
for (int frame = 0; frame < hca.FrameCount; frame++)
{
CryptFrame(hca, audio[frame], key, doDecrypt);
}
}
public static void DecryptFrame(HcaInfo hca, byte[] audio, CriHcaKey key)
{
for (int b = 0; b < hca.FrameSize; b++)
{
audio[b] = key.DecryptionTable[audio[b]];
}
}
public static void CryptFrame(HcaInfo hca, byte[] audio, CriHcaKey key, bool doDecrypt)
{
byte[] substitutionTable = doDecrypt ? key.DecryptionTable : key.EncryptionTable;
for (int b = 0; b < hca.FrameSize - 2; b++)
{
audio[b] = substitutionTable[audio[b]];
}
ushort crc = Crc.Compute(audio, hca.FrameSize - 2);
audio[hca.FrameSize - 2] = (byte)(crc >> 8);
audio[hca.FrameSize - 1] = (byte)crc;
}
private static bool TestKey(CriHcaFrame frame, byte[][] audio, CriHcaKey key, byte[] buffer)
{
int startFrame = FindFirstNonEmptyFrame(audio);
int endFrame = Math.Min(audio.Length, startFrame + FramesToTest);
for (int i = startFrame; i < endFrame; i++)
{
Array.Copy(audio[i], buffer, audio[i].Length);
CryptFrame(frame.Hca, buffer, key, true);
var reader = new BitReader(buffer);
if (!CriHcaPacking.UnpackFrame(frame, reader))
{
return(false);
}
}
return(true);
}
