Physical one-way functions

• Published in: Science (American Association for the Advancement of Science) Vol. 297; no. 5589; pp. 2026 - 2030
• Main Authors: PAPPU, Ravikanth, RECHT, Ben, TAYLOR, Jason, GERSHENFELD, Neil
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 20.09.2002; The American Association for the Advancement of Science
• Subjects: Applied sciences; Computer science; Computers; Cryptography; Digital computers; Exact sciences and technology; Information Security; Information, signal and communications theory; Number Concepts; Physics; Safety and security measures; Scientific Concepts; Signal and communications theory; Software/hardware leasing; Telecommunications and information theory; United States; Mesoscopic system; Cryptography; Message authentication; Transmission protocol
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1074376

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.