Feeds

Quantum crypto hack smacked

Implementation flaw only: 'perfect security' still coming

Top 5 reasons to deploy VMware with Tegile

A hack against systems running quantum key cryptography only worked because of implementation errors, according to new research.

A paper published in September demonstrated how the avalanche photo-detectors as used in quantum cryptography rigs might be blinded, essentially causing equipment to malfunction without generating an error indicating that a key exchange needed to be abandoned.

Using the ruse, a potential eavesdropper might be able to gain information about a secret encryption key being exchanged over a supposedly super-secure optical fibre link. Normally any attempt to observe the key exchange would interfere with the process, producing so many errors that a key exchange is abandoned.

However, in real world systems, errors do occur and systems might be tuned to compensate for this. The attack subverts these error detection features in such as a way that a potential eavesdropper could extract at least snippets of data from a key exchange while leaving users none the wiser that anything is amiss.

Commercial systems from MagiQ Technology's QPN 5505 and ID Quantique Clavis2 systems were shown to be potentially at risk from the attack by a team of computer scientists from Norway and Germany.

Computer scientists from Norwegian University of Science and Technology (NTNU), the University of Erlangen-Nürnberg and the Max Planck Institute for the Science of Light in Erlangen showed the crypto-busting technique was possible using off-the-shelf (though admittedly expensive, $50K) hardware. The boffins worked with manufacturers to resolve the problem, which revolved around real-world implementation mistakes, rather than anything wrong with the basic principles of quantum key cryptography, which remain rock solid.

Scientists at Toshiba’s Cambridge Research Laboratory evaluated the work, concluding that the detector blinding attack would fail to work against single photon detectors - providing the system was operating quickly. Straightforward adaptations on potentially vulnerable avalanche photo-detector systems would also thwart the attack, as the Toshiba team explains.

The attack is only successful if a redundant resistor is included in series with the single photon detector, or if the discrimination levels are set inappropriately. Furthermore, by monitoring the photocurrent generated by the detector, it is possible to prevent all bright light attacks on avalanche photodiodes.

The Cambridge-based boffins praised their fellow egg-heads, saying the blinding attack only goes to show that quantum cryptography systems are getting a thorough going over, a process that will likely result in better and more secure systems. Applications for quantum key cryptography include banking and government.

Dr Andrew Shields, assistant managing director at Toshiba Research Europe, commented: "Quantum cryptography is now entering a new phase in which the security of particular implementations is carefully analysed and tested. This is important to uncover any security loopholes and to devise appropriate countermeasures."

Shields added: "It will allow real-world devices to approach the perfect security that can be proven for the protocol."

The Toshiba team published their findings in the December edition of Nature Photonics, the same academic journal that published the original Norwegian/German research. ®

Internet Security Threat Report 2014

More from The Register

next story
'Kim Kardashian snaps naked selfies with a BLACKBERRY'. *Twitterati gasps*
More alleged private, nude celeb pics appear online
Home Depot ignored staff warnings of security fail laundry list
'Just use cash', former security staffer warns friends
Hackers pop Brazil newspaper to root home routers
Step One: try default passwords. Step Two: Repeat Step One until success
UK.gov lobs another fistful of change at SME infosec nightmares
Senior Lib Dem in 'trying to be relevant' shocker. It's only taxpayers' money, after all
Spies would need SUPER POWERS to tap undersea cables
Why mess with armoured 10kV cables when land-based, and legal, snoop tools are easier?
Who.is does the Harlem Shake
Blame it on LOLing XSS terroristas
Snowden, Dotcom, throw bombs into NZ election campaign
Claim of tapped undersea cable refuted by Kiwi PM as Kim claims extradition plot
Freenode IRC users told to change passwords after securo-breach
Miscreants probably got in, you guys know the drill by now
THREE QUARTERS of Android mobes open to web page spy bug
Metasploit module gobbles KitKat SOP slop
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.