Embedded systems in many applications consist of multiple different chips and are physically accessible to owners, users, and also possible adversaries. Therefore, they are at risk from attackers with advanced skills in electronics, communication engineering, implementation engineering or hardware attacks. Such attackers can also obtain access to internal interfaces, such as debugging interfaces, or interfaces of integrated memory chip directly. For these reasons, it is essential to target a high level of hardware security from the very beginning while designing such systems. A comprehensive and tailored design approach and the application of specific cryptographic algorithms is required to establish a high hardware security level according to the respectively relevant threats and circumstances. In most cases, the integration of dedicated security chips with specific features and properties into the embedded system is necessary to protect against such modern hardware attacks.
However, comprehensive security designs with standardised cryptographic algorithms for embedded systems are no longer enough. Adversaries have advanced skills in the side-channel analysis of cryptographic implementations and in fault attacks on such. For example, a key can be cracked by measuring the current consumption. It is therefore essential to use advanced protective measures.
A promising approach in the field of hardware security is the use of Physical Unclonable Functions (PUFs). One possible application of this technology is the derivation of cryptographic keys from the unique physical properties of individual chips of the same type. The resulting keys are ‘stored’ in the physical properties and are therefore extremely difficult to read out.