Source-linked AI summary
Quantum security and theory of decoherence
Piotr Mironowicz
TL;DR
The paper examines how environmental interactions required for quantum measurement challenge the shielded-laboratory assumption in quantum cryptography. Modeling a Van Eck-type eavesdropper, it derives a trade-off between guessing probability and decoherence, while showing that even a simple attack can compromise private randomness.
Problem
Quantum cryptography assumes private device outputs remain shielded, but decoherence theory assigns the external environment a central role in producing measurement and information leakage.
Method
The paper models qubit measurement through environment-mediated interactions and analyzes a passive Van Eck-type eavesdropper intercepting environmental information.
Results
For a realistic case with Γ ≈10^-40, intercepting 1% or 5% of the environment gives Pguess values of 0.6 or 0.99, respectively.
Takeaways & Limitations
The derived trade-off indicates that eavesdroppers’ ability to read measurement information limits decoherence, making private-number devices vulnerable to environmental wiretapping.
Takeaways & Limitations
The model covers only a particular, simplistic form of Van Eck-type attack and may not be the most efficient one.
Abstract
from arXiv · showhide
We sketch a relation between two crucial, yet independent, fields in quantum information research, viz. quantum decoherence and quantum cryptography. We investigate here how the standard cryptographic assumption of shielded laboratory, stating that data generated by a secure quantum device remain private unless explicitly published, is disturbed by the einselection mechanism of quantum Darwinism explaining the measurement process by interaction with the external environment. We illustrate the idea with a paradigmatic example of a quantum random number generator compromised by an analog of the Van Eck phreaking. In particular, we derive a trade-off relation between eavesdropper's guessing probability $P_{guess}$ and the collective decoherence factor $Γ$ of the simple form $P_{guess} + Γ\geq 1$.