public static DecrypterV106 Create(IBinaryReader reader)
{
try {
int keyXorOffs7 = (ReadByteAt(reader, 0) ^ ReadByteAt(reader, 2)) + 2;
reader.Position = keyXorOffs7 + (ReadByteAt(reader, 1) ^ ReadByteAt(reader, keyXorOffs7));
int sha1DataLen = reader.Read7BitEncodedInt32() + 0x80;
int keyXorOffs6 = (int)reader.Position;
int encryptedOffs = (int)reader.Position + sha1DataLen;
var sha1Data = reader.ReadBytes(sha1DataLen);
uint crc32 = CRC32.CheckSum(sha1Data);
reader.Position = reader.Length - 0x18;
uint origCrc32 = reader.ReadUInt32();
if (crc32 != origCrc32)
{
return(null);
}
var key0 = DeobUtils.Sha1Sum(sha1Data); // 1.0.6.0
var key6 = GetKey(reader, key0, keyXorOffs6); // 1.0.6.6
var key7 = GetKey(reader, key0, keyXorOffs7); // 1.0.6.7
return(new DecrypterV106(key0, key6, key7, encryptedOffs));
}
catch (IOException) {
return(null);
}
}