Physical One-Way Functions

Physical One-Way Functions (POWFs) were the subject of my doctoral dissertation at MIT.

The central result was to show that the physics of coherent transport through disordered 3D mesoscopic systems is capable of generating unique identifiers. This is accomplished by physically reducing the complicated 3D microstructure using a coherent probe (e.g., a laser beam) and recording the resulting speckle pattern. The speckle pattern is then reduced to a fixed-length string of binary digits to produce a unique identifier. The research showed that this process of generating identifiers has all the properties of a noisy one-way function used in cryptography. These physical one-way functions (now called Physical Unclonable Functions) are inexpensive to fabricate, prohibitively difficult to duplicate, admit no compact mathematical representation, and are intrinsically tamper-resistant.

This work has been cited over 2,500 times and continues to be an active area of research.