2013/11/30 by Cosmo Lupo, Mark M. Wilde, Seth Lloyd · 1 citation
Computer Science · Physics and Astronomy · #Computer network #Computer science #Computer security #Encryption #Information leakage #Key (lock) #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum cryptography #Quantum information #Quantum key distribution #Quantum mechanics #Theoretical computer science #quant-ph
paper · pdf · doi:10.1103/physreva.90.022326
published as Physical Review A vol. 90, no. 2, page 022326, August 2014 · A new result on the robustness of quantum data locking has been added
openalex publication_date 2014/08/25 · arxiv created 2014/08/29 · arxiv updated 2014/12/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Quantum data locking is a uniquely quantum phenomenon that allows a relatively short key of constant size to (un)lock an arbitrarily long message encoded in a quantum state, in such a way that an eavesdropper who measures the state but does not know the key has essentially no information about the message. The application of quantum data locking in cryptography would allow one to overcome the limitations of the one-time pad encryption, which requires the key to have the same length as the message. However, it is known that the strength of quantum data locking is also its Achilles heel, as the leakage of a few bits of the key or the message may in principle allow the eavesdropper to unlock a disproportionate amount of information. In this paper we show that there exist quantum data locking schemes that can be made robust against information leakage by increasing the length of the key by a proportionate amount. This implies that a constant size key can still lock an arbitrarily long message as long as a fraction of it remains secret to the eavesdropper. Moreover, we greatly simplify the structure of the protocol by proving that phase modulation suffices to generate strong locking schemes, paving the way to optical experimental realizations. Also, we show that successful data locking protocols can be constructed using random code words, which very well could be helpful in discovering random codes for data locking over noisy quantum channels.