private static void TryDecrypt(ABNDFileEntry entry, List <ABNDChunk> chunks)
{
Debug.Assert(entry.EncryptionType == EncryptionType.ChaCha);
uint totalLen = 0;
foreach (var chunk in chunks)
{
totalLen += chunk.Length;
}
var encrypted = GetConcatenatedEncryptedChunks(totalLen, chunks);
var IV = entry.IV;
var xor = IV.Xor(12);
var decrypted = ChaCha.Decrypt(encrypted, xor, entry.MAC);
if (decrypted == null)
{
throw new Exception();
}
// rechunk data
GetDecryptedChunks(chunks, decrypted);
}
public ABND(byte[] data)
{
Data = data;
Header = Util.GetSlice(data, 0, ABNDHeader.SIZE).ByteArrayToStructure <ABNDHeader>();
Debug.Assert(Header.Magic == MAGIC);
Debug.Assert(Header.ExtHeaderOffset == ABNDHeader.SIZE);
Debug.Assert(Header.ExtHeaderSize == ABNDExtHeader.SIZE);
ExtHeader = Util.GetSlice(data, Header.ExtHeaderOffset, Header.ExtHeaderSize).ByteArrayToStructure <ABNDExtHeader>();
Debug.Assert(ExtHeader.EncryptionType == EncryptionType.ChaCha);
var payload = Util.GetSlice(data, ExtHeader.EStringTableOffset, ExtHeader.EStringTableLength);
FileNameTable = ChaCha.Decrypt(payload, ExtHeader.IV, ExtHeader.MAC);
}