Secret key expansion from covert communication

Abstract

Covert communication allows us to transmit messages in such a way that it is not possible to detect that the communication is occurring. This provides protection in situations where knowledge that people are talking to each other may be incriminating to them. In this work, we study how covert communication can be used for a different purpose: secret key expansion. First, we show that any message transmitted in a secure covert protocol is also secret and therefore unknown to an adversary. We then propose a protocol that uses covert communication where the amount of key consumed in the protocol is smaller than the transmitted key, thus leading to secure secret key expansion. We derive precise conditions showing that secret key expansion from covert communication is possible when there are sufficiently low levels of noise for a given security level. We conclude by examining how secret key expansion from covert communication can be performed in a computational security model.

6 pages, 2 figures

References in corpus (7)

• Practical challenges in quantum key distribution
• Experimental measurement-device-independent quantum digital signatures over a metropolitan network
• Experimental transmission of quantum digital signatures over 90-km of installed optical fiber using a differential phase shift quantum key distribution system
• Experimental investigation of practical unforgeable quantum money
• Quantum money with nearly optimal error tolerance
• 24-Hour Relativistic Bit Commitment
• Absolutely covert quantum communication

Cited by in corpus (4)

• Two-way covert quantum communication in the microwave regime
• A framework for covert and secret key expansion over quantum channels
• Quantum cryptography beyond key distribution: theory and experiment
• Challenges in Covert Wireless Communications with Active Warden on AWGN channels