Low Cost Quantum Secret Key Growing for Consumer Transactions

Abstract

We present the design and development of a novel free-space quantum cryptography system complete with purpose-built software that can operate in daylight conditions. Current commercial quantum cryptography systems are expensive, use purpose-built components and are made-toorder. Their market base is primarily military, financial services or high intellectual property organisations. This work is a departure from this arena and represents a ground-up approach to quantum cryptography, exploring the possibilities of bringing secure electronic communication and data exchange to the consumer.The transmitter and receiver modules are built using inexpensive off-the-shelf components and are both compact allowing the generation of renewed identical keys on demand over a short range. A full software system has been developed to handle synchronization, error estimation and correction and privacy amplification. The intended application is the use of quantum secret key growing in the secure exchange of transaction information between a handheld transmitter and a

Quantum teleportation with infinite reference-frame uncertainty

“…A shared reference frame is an important implicit assumption underlying the correct execution of many multi-party quantum protocols [3,18,19,14,29,10,9]. As quantum technologies move into space [25,34,1] and into handheld devices [31,7,8], scenarios where this assumption is violated are naturally encountered. This problem has already received considerable attention in the case of ground-to-satellite quantum key distribution [15,16,1]; there is also a smaller body of work on quantum teleportation without a shared reference frame [5,20,21], a subject which is increasingly important as quantum repeaters [22] and ground-to-satellite quantum teleportation [25] become experimentally viable.…”

“…Outlook. Work has been done on reference frame-independent quantum key distribution between handheld devices sharing an optical link [31,7,8]; such devices seem an obvious application for our perfect scheme for U(1) uncertainty. There may also be cryptographic applications for these results, as it has been noted that a private shared reference frame may be used as a secret key [14,11,2], and our tight scheme does not leak reference frame information.…”

“…8 It is good to pick F so that all the readings in it are as close to the identity as possible under some metric. To make this precise one can use Voronoi cells[33].…”

Tight quantum teleportation without a shared reference frame

“…It is now well recognized that a shared reference frame is an implicit assumption underlying the correct execution of many quantum protocols [4,18,13,34,14,31]. As quantum communication finds its way into handheld devices [35,9,10] and into space [26,38,2], it is increasingly important to develop protocols robust against reference frame error for situations where alignment is difficult [16,17,28] or undesired [3,15]. Considerable progress has already been made in this regard for quantum key distribution [8,39,36,20,29,19,30], and there is also a smaller body of work on quantum teleportation [6,21,22] without a shared reference frame, which our results extend.Main results.…”