paper: https://www.usenix.org/sites/default/files/sec15_supplement.pdf https://www.usenix.org/sites/default/files/sec15_supplement.... "The transponder uses a

paper: https://www.usenix.org/sites/default/files/sec15_supplement.pdf https://www.usenix.org/sites/default/files/sec15_supplement.... "The transponder uses a 96-bit secret key and a proprietary cipher in order to authenticate to the vehicle." not sure there's anything more you need to know than "rolled their own crypto"