Feeds

Optical boffins cut the cost of quantum cryptography

Time shift dances the light fantastic

High performance access to file storage

Boffins at the National Institute of Standards and Technology are trialling advanced optical techniques aimed at reducing the price of quantum cryptography systems.

The new quantum key distribution approach reduces the required number of single photon detectors, which can cost anything between $5K-$20K and are the most costly component of quantum cryptography systems.

Quantum cryptography allows two users on an optical fibre network to exchange secret keys. Each bit of the key is encoded upon a single light particle (or 'photon'). Intercepting this data randomly changes the polarization of the light, irreversibly altering the data.

Because of this quantum mechanics effect any attempt by an eavesdropper to determine a key corrupts the same key with noise. Quantum cryptography systems discard these corrupt keys and only use codes that are known to be secure. These quantum keys, once exchanged, can be used in a one-time pad.

Conventional cryptography setups involve at least two photon detectors, and more commonly four. By adding an optical component that delays the travel of photons to the detector, NIST researchers have been able to halve the number of detectors needed.

The most common polarization-based protocol, BB84, uses four single-photon detectors. One pair of detectors looks for photons with either vertical or horizontal polarization, which signify either 0 or 1. The other set of detectors record diagonally polarized photons.

NIST researchers have reduced the number of detectors required by using an optical component to make these diagonally polarized photons rotate by a further 45 degrees and arrive at the horizontal/vertical detector, but slightly later than photons that started off with this orientation. As such the approach is a type of time division multiplexing.

The same technique was used to number of detectors needed to implement the B92 protocol from two to one.

The approach cuts transmission rates by half but the advantage of lower costs far outweighs this minor disadvantage. The NIST team, led by researcher Xiao Tang, reckon the approach avoids introducing noise and might actually be more secure than conventional approaches.

NIST researchers intend to explain their detection time bin shift (DTBS) scheme in a paper due to be published by the IEEE Communications Letters next month.

In additional research carried out after the publication of this paper, the NIST team has further developed its approach so that the popular BB84 protocol requires only one detector instead of four.

A summary of the research, including diagrams, can be found on the NIST website. ®

High performance access to file storage

More from The Register

next story
Parent gabfest Mumsnet hit by SSL bug: My heart bleeds, grins hacker
Natter-board tells middle-class Britain to purée its passwords
Samsung Galaxy S5 fingerprint scanner hacked in just 4 DAYS
Sammy's newbie cooked slower than iPhone, also costs more to build
Obama allows NSA to exploit 0-days: report
If the spooks say they need it, they get it
Web data BLEEDOUT: Users to feel the pain as Heartbleed bug revealed
Vendors and ISPs have work to do updating firmware - if it's possible to fix this
Snowden-inspired crypto-email service Lavaboom launches
German service pays tribute to Lavabit
One year on: diplomatic fail as Chinese APT gangs get back to work
Mandiant says past 12 months shows Beijing won't call off its hackers
Call of Duty 'fragged using OpenSSL's Heartbleed exploit'
So it begins ... or maybe not, says one analyst
NSA denies it knew about and USED Heartbleed encryption flaw for TWO YEARS
Agency forgets it exists to protect communications, not just spy on them
prev story

Whitepapers

Securing web applications made simple and scalable
In this whitepaper learn how automated security testing can provide a simple and scalable way to protect your web applications.
Five 3D headsets to be won!
We were so impressed by the Durovis Dive headset we’ve asked the company to give some away to Reg readers.
HP ArcSight ESM solution helps Finansbank
Based on their experience using HP ArcSight Enterprise Security Manager for IT security operations, Finansbank moved to HP ArcSight ESM for fraud management.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Mobile application security study
Download this report to see the alarming realities regarding the sheer number of applications vulnerable to attack, as well as the most common and easily addressable vulnerability errors.