Strong authentication with physical unclonable functions

Physical unclonable functions (PUFs) can be used as a cost-effective means to store cryptographic key material in an unclonable way. They can be employed for strong authentication of objects, e.g., tokens, and of persons possessing such tokens, but also for other purposes. We give a short overview of security applications where PUFs are useful, and discuss physical realisations, noisy measurements and information content of PUFs. Then we describe an integrated authentication token containing an optical PUF, a challenging mechanism and a detector. Finally, we discuss authentication protocols for controlled and uncontrolled PUFs