5. Laser Fault Injection

In this chapter, we demonstrate the vulnerabilities of the soft PUF implementations on the reconfigurable hardware against LFI attacks. The building blocks of a soft PUF implementation are realized by identical programmable logic cells. It is evident that any faults in the configuration memory of deployed logic cells change the logical functionality of that cell, and consequently, could affect the PUF behavior. We present an LFI attack against PoC XOR Arbiter PUF and RO PUF implementations used in the key generation and authentication scenarios. As a result, fault injection enables us to deactivate different PUF chains in an XOR Arbiter PUF, which simplifies a modeling attack against such architectures. In a similar way, we can disable arbitrarily chosen ring oscillators in different RO PUF variants to reduce and bias the entropy of the generated numbers.