title: Physical one-way functions.
abstract: Modern cryptographic practice rests on the use of one-way functions, which are easy to evaluate but difficult to invert. Unfortunately, commonly used one-way functions are either based on unproven conjectures or have known vulnerabilities. We show that instead of relying on number theory, the mesoscopic physics of coherent transport through a disordered medium can be used to allocate and authenticate unique identifiers by physically reducing the medium's microstructure to a fixed-length string of binary digits. These physical one-way functions are inexpensive to fabricate, prohibitively difficult to duplicate, admit no compact mathematical representation, and are intrinsically tamper-resistant. We provide an authentication protocol based on the enormous address space that is a principal characteristic of physical one-way functions.
authors.affiliation: Center for Bits and Atoms, The MIT Media Labs, 20 Ames Street, Cambridge, MA 02139, USA. ravi@thingmagic.com
authors.forename: Ravikanth
authors.initials: R
authors.lastname: Pappu
authors.forename: Ben
authors.initials: B
authors.lastname: Recht
authors.forename: Jason
authors.initials: J
authors.lastname: Taylor
authors.forename: Neil
authors.initials: N
authors.lastname: Gershenfeld