2016/01/25 by Bullock, Michael S., Azadeh Sheikholeslami, Sheikholeslami, Azadeh +6 · 4 citations
Computer Science · Psychology · #Adversarial Robustness in Machine Learning #Deception detection and forensic psychology #FOS: Computer and information sciences #FOS: Physical sciences #Information Theory (cs.IT) #Internet Traffic Analysis and Secure E-voting #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.1601.06826
openalex publication_date 2016/01/25 · openalex created_date 2022/10/04 · openalex updated_date 2026/07/28
We investigate covert communication over general memoryless classical-quantum channels with fixed finite-size input alphabets. We show that the square root law (SRL) governs covert communication in this setting when product of n input states is used: L\rm SRL√(n)+o(√(n)) covert bits (but no more) can be reliably transmitted in n uses of classical-quantum channel, where L\rm SRL>0 is a channel-dependent constant that we call covert capacity. We also show that ensuring covertness requires J\rm SRL√(n)+o(√(n)) bits secret shared by the communicating parties prior to transmission, where J\rm SRL≥0 is a channel-dependent constant. We assume a quantum-powerful adversary that can perform an arbitrary joint (entangling) measurement on all n channel uses. We determine the single-letter expressions for L\rm SRL and J\rm SRL, and establish conditions when J\rm SRL=0 (i.e., no pre-shared secret is needed). Finally, we evaluate the scenarios where covert communication is not governed by the SRL.