A method for safeguarding a system-on-a-chip includes a hardware-programmable logic unit. In the course of a programming process, a public PUF key and a private PUF key are generated in the hardware-programmable logic unit with the aid of a physical unclonable function, and the public PUF key is signed with the aid of a second private key. The public PUF key and its signature are stored in an external memory of the system-on-a-chip, a security module is signed with the aid of a third private key, the security module and its signature are stored in the external memory of the system-on-a-chip, and the security module includes software which is used for safeguarding the system-on-a-chip.