Its a RSA-1024 bit Digital Signature, really hard to be brute force defeated, needs proprietary key for OBD2 flashing.What bit strength and which algorithm does VW use?
Also need backdoor security access to read/write to the ecu at the hardware level.
It even has a hardware firewall on one of the memories.
Each engine sensor has an RSA key.
1024-bit encryption is crackable. The idea is never to make something totally secure, but to make it enough of a time sink as to not be worth the trouble and profitable.