QKD Based on Symmetric Entangled Bernstein-Vazirani

Abstract

This paper introduces a novel entanglement-based QKD protocol, that makes use of a modified symmetric version of the Bernstein-Vazirani algorithm, in order to achieve secure and efficient key distribution. Two variants of the protocol, one fully symmetric and one semi-symmetric, are presented. In both cases, the spatially separated Alice and Bob share multiple EPR pairs, each one qubit of the pair. The fully symmetric version allows both parties to input their tentative secret key from their respective location and acquire in the end a totally new and original key, an idea which was inspired by the Diffie-Hellman key exchange protocol. In the semi-symmetric version, Alice sends her chosen secret key to Bob (or vice versa). The performance of both protocols against an eavesdroppers attack is analyzed. Finally, in order to illustrate the operation of the protocols in practice, two small scale but detailed examples are given.

A Two-Party Quantum Parliament

“…In (27), which is in agreement with (19), parameters θ and ϕ refer to the elevation and azimuth angles, respectively, of the Bloch sphere. Parameter λ corresponds to a global phase factor that is physically unobservable.…”

“…One may recall that cryptographic protocols are usually presented as games between the two fictional heroes Alice and Bob, who are the two remote parties trying to safely exchange messages. A typical and convincing example is the quantum game of coin tossing and its relation to the BB84 protocol (see [25,26] and the more recent [27]). This setting has already been generalized to higher dimensions in [28].…”

QKeyShield: A Practical Receiver-Device-Independent Entanglement-Swapping-Based Quantum Key Distribution

“…When q total is sufficiently large, QKeyShield's efficiency can be made asymptotically close to 100%. Figure 7 shows numerical comparison in terms of finite secret key rate between three approaches: memoryassisted protocols [52], [51]; random-based protocols with with the help of quantum memory and classical messages, a deterministic approach is used in several protocols [31], [12], [14], [49] and 50% of the obtained bits end up in the sifted key. (b) QKeyShield uses the biased approach; thus, the estimated proportion of bits with operators conflicts drops from half to 2 * p * (1 − p) × q total and the estimated proportion of bits that end up in the sifted key increases to (p 2 −(1−p) 2 )×q total .…”

A symmetric extensible protocol for quantum secret sharing

“…As a consequence quantum games have gained prominence as a useful paradigm of the quantum world and have been used to tackle important problems. A typical example in this area is the quantum game of coin tossing and its application to cryptographic protocols (see [22], [23] and the more recent [24]). The beginning of this field can be traced back to two landmark papers from 1999: Meyer's PQ penny flip game [25] and the Eisert-Wilkens-Lewenstein scheme [26].…”