Atomic-scale authentication with Resonant Tunnelling Diodes

As technology has progressed, the trust of everyday interactions has inadvertently been undermined by the sophistication and availability of modern resources. To handle this issue, authentication strategies are implemented to provide proof of identities. Devices providing unique and reproducible fingerprints in response to an applied challenge can supply such identities. To generate these distinct signatures, physically unclonable functions (PUFs)1 are commonly utilised. The imperfect manufacturing process used to fabricate these devices provides structures that contain inherent randomness whilst containing a physical attribute that is simple to measure. Due to their physical nature, these structures do not rely on the privacy of stored secrets and can provide hard-to-predict unique identities for authentication in response to a challenge. However, the character of their classical design not only limits their size but also causes vulnerabilities in their security. In our recent work2, we show that the broadly studied fluctuations in the current-voltage spectra of resonant tunnelling diodes (RTDs) containing a variety of nanostructures presents a straightforward yet robust measurement that can function as a PUF without conventional resource restrictions. We show an illustration of this in the inset of Fig. 1, here the atomic imperfections of a quantum dot display an example of the maximum degree of quantum uniqueness. We have coined structures demonstrating such quantum variations QUFs – quantum unclonable functions3. As we show in Fig.1, these devices produce a series of peak profiles in their current-voltage characteristics due to negative differential resistance being exhibited in the region where resonant tunnelling takes place. We show that the measured current-voltage spectrum provides each device with a high degree of uniqueness as they rely upon the atomic structure and composition of the nanostructure within the RTD. Moreover, the devices are impossible to clone or simulate, even with state-of-the-art technology. Thus, we have shown that it is possible to make room-temperature operating PUF-like devices that require the fewest resources and make use of quantum phenomena in a highly manufacturable electronic device. Standard spectral analysis methods, when pertained to our QUFs, will facilitate consistent production of unpredictable unique identities which can be implemented in complex authentication schemes