A processor system includes a processor and a first memory area storing a boot program code. The boot program code starts execution of the operating system when executed by the processor, performs a cryptographic operation when processor executes the boot program code. A second memory area stores one or more cryptographic keys and is only accessible to the boot program code. A third memory stores the operating system. A communication interface receives data over a communication network. The processor retrieves the boot program code from the first memory area and executes the boot program code to start execution of the operating system. The processor terminates execution of the boot program code. The processor is configured to re-execute the boot program code while the operating system is executed to cryptographically encrypt data upon the basis of the cryptographic keys stored in the second memory area.