Quote Originally Posted by GMPX View Post
Guys, there is no encryption on these ECM's, lets get the terminology correct.
There is a password on the 'back door' as it was put (and sorry, it is 64 bit, not 128), but either way you ain't getting in unless you know it. This is the password that protects the ECM from being opened up and the flash dumped out using JTAG tools (Google PowerPC censorship password).
The flash segments again are not encrypted in any way, they just have a SHA-256 signature included that nobody other than GM can calculate with their private key that must be sent and validated during the OBD-II flash.
So yes doors are closed and the keys broken off in the lock, nothing to see here folks please move on to your nearest Dodge or FORD dealership.
2017 FORD is in need of a locksmith as well it seems.