A tamper-indicating quantum seal

TL;DR

This paper introduces a quantum seal using entanglement and photon polarization to detect tampering with extremely high confidence, surpassing classical fiber optic seals in security against spoofing and interception attacks.

Contribution

The development of a quantum seal employing entanglement and the Hong-Ou-Mandel effect to detect tampering with unprecedented accuracy and security.

Findings

Detection probability > 0.9999 within 10 seconds

False alarm rate of 10^{-9}

Limits on path length change to sub-millimeter disturbances

Abstract

Technical means for identifying when tampering occurs is a critical part of many containment and surveillance technologies. Conventional fiber optic seals provide methods for monitoring enclosed inventories, but they are vulnerable to spoofing attacks based on classical physics. We address these vulnerabilities with the development of a quantum seal that offers the ability to detect the intercept-resend attack using quantum integrity verification. Our approach represents an application of entanglement to provide guarantees in the authenticity of the seal state by verifying it was transmitted coherently. We implement these ideas using polarization-entangled photon pairs that are verified after passing through a fiber-optic channel testbed. Using binary detection theory, we find the probability of detecting inauthentic signals is greater than 0.9999 with a false alarm chance of $10^{-9}$ for a 10 second sampling interval. In addition, we show how the Hong-Ou-Mandel effect concurrently provides a tight bound on redirection attack, in which tampering modifies the shape of the seal. Our measurements limit the tolerable path length change to sub-millimeter disturbances. These tamper-indicating features of the quantum seal offer unprecedented security for unattended monitoring systems.