/// <summary>
/// Decrypts and unpacks DS2's regulation BND4 from the specified path.
/// </summary>
public static BND4 DecryptDS2Regulation(string path)
{
byte[] bytes = File.ReadAllBytes(path);
byte[] iv = new byte[16];
iv[0] = 0x80;
Array.Copy(bytes, 0, iv, 1, 11);
iv[15] = 1;
byte[] input = new byte[bytes.Length - 32];
Array.Copy(bytes, 32, input, 0, bytes.Length - 32);
using (var ms = new MemoryStream(input))
{
byte[] decrypted = CryptographyUtility.DecryptAesCtr(ms, ds2RegulationKey, iv);
return(BND4.Read(decrypted));
}
}
private void ReadCtr(Stream inputStream)
{
BigEndianBinaryReader reader = new BigEndianBinaryReader(inputStream, Encoding.ASCII, true);
_iv[00] = 0x80;
for (int i = 1; i <= 11; i++)
{
_iv[i] = reader.ReadByte();
}
_iv[12] = 0x00;
_iv[13] = 0x00;
_iv[14] = 0x00;
_iv[15] = 0x01;
inputStream.Seek(EncryptionIvCtrSize, SeekOrigin.Begin);
byte[] encryptedData = reader.ReadBytes((int)inputStream.Length - EncryptionIvCtrSize);
Data = CryptographyUtility.DecryptAesCtr(new MemoryStream(encryptedData), _key, _iv);
}