2 research outputs found
An Improved Asymptotic Key Rate Bound for a Mediated Semi-Quantum Key Distribution Protocol
Semi-quantum key distribution (SQKD) protocols allow for the establishment of
a secret key between two users Alice and Bob, when one of the two users
(typically Bob) is limited or "classical" in nature. Recently it was shown that
protocols exists when both parties are limited/classical in nature if they
utilize the services of a quantum server. These protocols are called mediated
SQKD protocols. This server, however, is untrusted and, in fact, adversarial.
In this paper, we reconsider a mediated SQKD protocol and derive a new proof of
unconditional security for it. In particular, we derive a new lower bound on
its key rate in the asymptotic scenario. Furthermore, we show this new lower
bound is an improvement over prior work, thus showing that the protocol in
question can tolerate higher rates of error than previously thought
Semi-Quantum Cryptography
Semi-quantum communication, a model introduced in 2007 by M. Boyer, D.
Kenigsberg, and T. Mor (PRL 99 140501), involves the use of fully-quantum users
and semi-quantum, or "classical" users. These restricted users are only allowed
to interact with the quantum channel in a limited manner. Originally introduced
to study the key-distribution problem, semi-quantum research has since
expanded, and continues to grow, with new protocols, security proof methods,
experimental implementations, and new cryptographic applications beyond key
distribution. Research in the field of semi-quantum cryptography requires new
insights into working with restricted protocols and, so, the tools and
techniques derived in this field can translate to results in broader quantum
information science. Furthermore, other questions such as the connection
between quantum and classical processing, including how classical information
processing can be used to counteract a quantum deficiency in a protocol, can
shed light on important theoretical questions.
This work surveys the history and current state-of-the-art in semi-quantum
research. We discuss the model and several protocols offering the reader
insight into how protocols are constructed in this realm. We discuss security
proof methods and how classical post-processing can be used to counteract
users' inability to perform certain quantum operations. Moving beyond key
distribution, we survey current work in other semi-quantum cryptographic
protocols and current trends. We also survey recent work done in attempting to
construct practical semi-quantum systems including recent experimental results
in this field. Finally, as this is still a growing field, we highlight,
throughout this survey, several open problems that we feel are important to
investigate in the hopes that this will spur even more research in this topic.Comment: Comments welcom