| Paper ID | D1-S3-T4.3 |
| Paper Title |
Covert Communication via Non-Causal Cribbing from a Cooperative Jammer |
| Authors |
Hassan ZivariFard, University of Texas at Dallas, United States; Matthieu Bloch, Georgia Institute of Technology, United States; Aria Nosratinia, University of Texas at Dallas, United States |
| Session |
D1-S3-T4: Covert Communication |
| Chaired Session: |
Monday, 12 July, 22:40 - 23:00 |
| Engagement Session: |
Monday, 12 July, 23:00 - 23:20 |
| Abstract |
We consider the problem of covert communication in the presence of a cooperative jammer. Covert communication refers to communication that is undetectable by an adversary, i.e., a scenario in which, despite ongoing communication, the output distribution observed by an adversary called the ``warden'' is indistinguishable from the distribution that would have been induced by an innocent channel-input symbol. It is known that in general, a transmitter and a receiver can communicate only $O(\sqrt{n})$ covert bits over $n$ channel uses, i.e., zero rate. This paper shows that a cooperative jammer can facilitate the communication of positive covert rates, subject to the transmitter having non-causal access to the jammer signal. An achievable rate region is calculated that highlights the relation between the covert communication rate, jammer's randomness (expressed as a rate), and rate of a secret key shared between transmitter and receiver.
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