3 ms·

Do you have a good source where could learn more about rolling codes & cryptography immobilizers? The wiki for it just brushes over it. https://en.wikipedia.or

• bri3d 2y ago
  Here's some basics about older systems: https://www.researchgate.net/publication/346706377_Dismantling_DST80-based_Immobiliser_Systems https://www.researchgate.net/publication/346706377_Dismantli... https://www.researchgate.net/publication/235916472_Gone_in_360_Seconds_Hijacking_with_Hitag2 https://www.researchgate.net/publication/235916472_Gone_in_3... https://blog.cryptographyengineering.com/2011/09/24/where-things-fall-apart-protocols-part/ https://blog.cryptographyengineering.com/2011/09/24/where-th... Newer systems use AES, which is at least less cryptographically unsound than the LFSR-based systems like Hitag2. Microchip present an interesting theoretical approach to AES-based immobilizer authentication here: https://ww1.microchip.com/downloads/en/DeviceDoc/article_open_immob_system.pdf https://ww1.microchip.com/downloads/en/DeviceDoc/article_ope... Note that these all focus on the key-authentication side. The inter-module communication ranges from completely insecure (like in the parent article - the key module says "OK, the key is auth'd!" and then just blasts an unauthenticated CAN message) to some variant of the key authentication strategy. For example, newer VW immobilizers use an AES-based nonce+MAC strategy similar to the theoretical Microchip one for both key communication _and_ module-to-module communication on the CAN bus.