Virtual Proofs of Reality, or: How to Prove Physical Statements over Digital Communication Lines

07.03.2018, 16:30 – 17:30

07.03.2018 16:30-17:30

Speaker: Dr. Ulrich Rührmair, Ruhr University Bochum | Location: Mornewegstraße 32 (S4|14), Room 3.1.01, Darmstadt

Organizer: Nikolaos Athanasios Anagnostopoulos, TU Darmstadt

Snacks and time for discussion afterwards.


What is the most virulent Achilles heel of modern cryptography and hardware security? It could be argued that these are the digital secrets or keys that need to be stored permanently, but securely in hardware. Both physical attacks and malware can potentially get hold of these keys, possibly leading to security issues.

Physical Unclonable Functions (PUFs), which were invented at MIT more than a decade ago, have shown us that certain cryptographic tasks can be accomplished without permanently stored digital secrets in the hardware, however. They surprisingly enable fundamental schemes like identification or tamper-sensing without classical keys.

Our talk deals with a recent extension of this concept. We pose the general question whether certain physical statements (such as “the temperature of a certain object O is X° Celsius”, or “a certain object O has been destroyed”, or “two objects O1 and O2 are at a distance D to each other”, or “a certain being/animal is alive”) can be proven over digital communication lines without using classical, permanent digital keys in the hardware of the prover. Our question is actually answered to the affirmative, and we present protocols and proof-of-concept implementations for all four example statements above. The corresponding schemes are called “Virtual Proofs of Reality” by us. Our talk builds upon a recent publication on the same topic from IEEE S&P 2015.

Short Bio

Dr. Dr. Ulrich Rührmair is a Junior Group Leader on “Physical Cryptography and Physical Security” at the Ruhr University Bochum. He holds an MSc from Oxford, one PhD from TU Berlin, and another PhD from TU Munich, where he has founded and for several years led the so-called physical cryptography project. His research generally deals with physical unclonable functions, physical cryptography and physical security, as well as with complexity theory, cryptography, and security at large.

Most recently, he became interested in novel disorder-based primitives beyond PUFs: For example, SIMPL Systems, which are a public key variant of PUFs, or Virtual Proofs of Reality, which aim to prove physical statements over digital communication lines. Ulrich has co-authored over 50 papers on the topic, and has served regularly on the program committees of leading conferences in the area, including IEEE S&P, CHES, and HOST. He is the founder and co-organizer of the ASHES workshop at ACM CCS.