Direct and Reverse Secret-Key Capacities of a Quantum Channel

Stefano Pirandola, Raul Garcia-Patron Sanchez, Samuel L. Braunstein, Seth Lloyd

Research output: Contribution to journalArticlepeer-review


We define the direct and reverse secret-key capacities of a memoryless quantum channel as the optimal rates that entanglement-based quantum-key-distribution protocols can reach by using a single forward classical communication (direct reconciliation) or a single feedback classical communication (reverse reconciliation). In particular, the reverse secret-key capacity can be positive for anti degradable channels, where no forward strategy is known to be secure. This property is explicitly shown in the continuous variable framework by considering arbitrary one-mode Gaussian channels.
Original languageEnglish
Article number050503
Number of pages1
JournalPhysical Review Letters
Issue number5
Publication statusPublished - 4 Feb 2009


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