Secure boot of vehicular processors

Among other things, techniques for securely booting processors in a vehicle are described. An apparatus comprises a circuit coupled to one or more processors of a vehicle and managing a secure boot process for the processors. The circuit receives an indication that the vehicle has been powered on and sends, to a network server, a request for boot files for the processors of the vehicle. In response, the circuit receives, from the server, most recent versions of boot files respectively corresponding to the processors, wherein each boot file includes a digital signature of a trusted authority. In response to obtaining the most recent versions of the boot files, the circuit sequentially boots the processors using the respective boot files, wherein each processor executes a corresponding boot file upon verifying authenticity of the digital signature in the boot file using a corresponding class authentication key.