Quantum Authentication and Encryption with Key Recycling

Understand

We propose an information-theoretically secure encryption scheme for classical messages with quantum ciphertexts that offers detection of eavesdropping attacks, and re-usability of the key in case no eavesdropping took place: the entire key can be securely re-used for encrypting new messages as long as no attack is detected.

• This is known to be impossible for fully classical schemes, where there is no way to detect plain eavesdropping attacks.
• This particular application of quantum techniques to cryptography was originally proposed by Bennett, Brassard and Breidbart in 1982, even before proposing quantum-key-distribution, and a simple candidate scheme was suggested but no rigorous security analysis was given.
• The idea was picked up again in 2005, when Damgard, Pedersen and Salvail suggested a new scheme for the same task, but now with a rigorous security analysis.