Capacity-based random codes cannot achieve strong secrecy over symmetric wiretap channels

Laura Luzzi (1) , Matthieu Bloch (2, 3)

1 Chaire Radio Flexible - Chaire Radio Flexible Alcatel-Lucent/Supélec
2 Georgia Tech Lorraine [Metz]
3 FEMTO-ST - Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174)

In this paper, we investigate the limitations of capacity-based random code constructions for the wiretap channel, i.e., constructions that associate to each con dential message a subcode whose rate approaches the capacity of the eavesdropper's channel. Generalizing a previous result for binary symmetric channels, we show that random capacity-based codes do not achieve the strong secrecy capacity over the symmetric discrete memoryless channels they were designed for. However, we also show that these codes can achieve strong secrecy rates provided they are used over degraded wiretap channels.

Domains: Computer Science [cs]; Information Theory [cs.IT]; Mathematics [math]; Information Theory [math.IT]

Laura Luzzi, Matthieu Bloch. Capacity-based random codes cannot achieve strong secrecy over symmetric wiretap channels. Securenets 2011, 2011, Cachan, France. 7 p. ⟨hal-00648147⟩