Ph.D. Defence Roel Maes - Physically Unclonable Functions: Constructions, Properties and Applications
Start date: 31/08/2012
Location: Promotiezaal, 01.46, Naamsestraat 22, 3000 Leuven
In my thesis I study a relatively new physical security primitive called "physically unclonable function" or PUF. A PUF is able to measure the uniqueness of the physical object it is embedded in. Every physical object is to a certain extent unique, even if thousand or millions of similar objects were produced in exactly the same manner. This is the result of microscopic details during production which cannot be fully controlled, but are to some extent random. An example of this phenomenon can be found in the fabrication of electronic microchips. Thousands of chips which are produced according to the same process, though they will have the same "logic" functionality, will have relatively significant differences in their electronic behavior caused by the uncontrollable randomness during production. A PUF which is integrated in the microchip is able to measure these unique electronic parameters and express them as a binary value. This value is hence a funtion of the unique physical properties of the specific chip it is derived from, and in that respect it is very similar to a fingerprint of a human being which is also unique and strictly personal. In the same way as persons are identified by means of their fingerprints, microchips can be identified by their PUF response. With adapted operations, the PUF response can even be processed into a secure key which can deployed directly in a cryptographic algorithm running on the same chip. Such a PUF-based key has a very high degree of physical security since it is derived from the intrinsic randomness of the microchip, which cannot be controlled or measured in an external manner.
In the thesis, existing and new constructions, properties and applications of PUFs are studied and proposed.