Feeds

Optical boffins cut the cost of quantum cryptography

Time shift dances the light fantastic

Internet Security Threat Report 2014

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. ®

Internet Security Threat Report 2014

More from The Register

next story
George Clooney, WikiLeaks' lawyer wife hand out burner phones to wedding guests
Day 4: 'News'-papers STILL rammed with Clooney nuptials
Shellshock: 'Larger scale attack' on its way, warn securo-bods
Not just web servers under threat - though TENS of THOUSANDS have been hit
Apple's new iPhone 6 vulnerable to last year's TouchID fingerprint hack
But unsophisticated thieves need not attempt this trick
PEAK IPV4? Global IPv6 traffic is growing, DDoS dying, says Akamai
First time the cache network has seen drop in use of 32-bit-wide IP addresses
Oracle SHELLSHOCKER - data titan lists unpatchables
Database kingpin lists 32 products that can't be patched (yet) as GNU fixes second vuln
Who.is does the Harlem Shake
Blame it on LOLing XSS terroristas
Researchers tell black hats: 'YOU'RE SOOO PREDICTABLE'
Want to register that domain? We're way ahead of you.
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
The next step in data security
With recent increased privacy concerns and computers becoming more powerful, the chance of hackers being able to crack smaller-sized RSA keys increases.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.