UK crypto boffins turbo-charge quantum cryptography

Photodiodes get go-faster stripes


Boffins at Toshiba’s Cambridge Research Labs have developed a technique for turbo-charging the speed of quantum cryptography transmissions.

Quantum key distribution (QKD) systems currently operate at dial-up rates of less than 10 kbps for 20km, making them suitable only for point-to-point links. The Cambridge researchers have developed a technique for boosting these speeds by a factor of a hundred, increasing rates of transmission to above 1Mbps.

Crypto researchers have been able to boost transmission rates from the dial-up to broadband range. They used a single photon detector developed by Toshiba, which can work 100-times faster than earlier devices. Toshiba explains:

Current QKD systems are limited by the semiconductor devices (avalanche photodiodes) used to detect the single photons. One photon triggers an avalanche of millions of electrons in this semiconductor device which can be sensed by electrical circuitry in the QKD system. The problem in present systems is that some of these avalanche electrons can be trapped in the device and later stimulate a second spurious detection count. As these noise counts cause errors in the key, current detectors must be operated with long dead times to allow the decay of any trapped electrons. This limits the clock rate of current QKD systems to around 10 MHz and thus the secure key bit rate to under 10kbps for a 20 km fibre.

The Toshiba team has devised a method to detect much weaker electron avalanches. This strongly reduces the chance for an electron to be trapped, allowing the detector to be operated at much faster rates. Using this method Toshiba has increased the clock rate of their QKD system to 1.036 GHz, approaching the value used in conventional optical communications. This allows a raw bit rate of 9Mbps over 20 km of fibre, which in turn provides 1.02 Mbps of secure key. This is the first time that a secure bit rate exceeding 1Mbps has been achieved.

Although Toshiba's advance offers the possibility of creating kickass quantum crypto networks that support multiple users, the technology is unlikely to be commercially available for some time. Toshiba researchers have only demonstrated the advance in the lab and are yet to build even a fully functional prototype.

Nonetheless Toshiba said its technique allows a form of encryption that is theoretically unhackable for optical fibre networks connecting far more users than was previously possible. More information about Toshiba's research in quantum crypto can be found here.

News of Toshiba's research comes alongside the launch of a quantum cryptography network in Vienna, Austria, as part of a collaboration between crypto boffins across Europe on the SECOQC project. This network is based in part on older, lower-speed technology from Toshiba, which makes it unable to support more than eight users on a quantum cryptography network at any time.

Quantum cryptography systems are designed to allow the exchange of secret keys which can then be used in one-time pads, creating a theoretically unhackable system for the secure exchange and authentication of messages. The polarisation of individual light photons is used to signify each bit of a key.

The rules of quantum mechanics mean that any eavesdropper who intercepts this stream of photons will be unable to simply relay the data stream intact. Because of this effect, any attempt to eavesdrop on a quantum cryptography key would come across as a corrupt transmission across a unacceptable noisy link. Such keys would be dropped and transmission repeated until exchanges without interception take place. ®

Similar topics

Broader topics


Other stories you might like

  • Protecting data now as the quantum era approaches
    Startup QuSecure is the latest vendor to jump into the field with its as-a-service offering

    Analysis Startup QuSecure will this week introduce a service aimed at addressing how to safeguard cybersecurity once quantum computing renders current public key encryption technologies vulnerable.

    It's unclear when quantum computers will easily crack classical crypto – estimates range from three to five years to never – but conventional wisdom is that now's the time to start preparing to ensure data remains encrypted.

    A growing list of established vendors like IBM and Google and smaller startups – Quantum Xchange and Quantinuum, among others – have worked on this for several years. QuSecure, which is launching this week after three years in stealth mode, will offer a fully managed service approach with QuProtect, which is designed to not only secure data now against conventional threats but also against future attacks from nation-states and bad actors leveraging quantum systems.

    Continue reading
  • Cheers ransomware hits VMware ESXi systems
    Now we can say extortionware has jumped the shark

    Another ransomware strain is targeting VMware ESXi servers, which have been the focus of extortionists and other miscreants in recent months.

    ESXi, a bare-metal hypervisor used by a broad range of organizations throughout the world, has become the target of such ransomware families as LockBit, Hive, and RansomEXX. The ubiquitous use of the technology, and the size of some companies that use it has made it an efficient way for crooks to infect large numbers of virtualized systems and connected devices and equipment, according to researchers with Trend Micro.

    "ESXi is widely used in enterprise settings for server virtualization," Trend Micro noted in a write-up this week. "It is therefore a popular target for ransomware attacks … Compromising ESXi servers has been a scheme used by some notorious cybercriminal groups because it is a means to swiftly spread the ransomware to many devices."

    Continue reading
  • Toshiba says it's talking to 10 suitors about possible sale
    Hires external advisors to bolster decision making capacity and hints it could consider multiple buyout plans

    Ailing Japanese giant Toshiba has revealed it has 10 potential suitors for its possible sale.

    A Friday announcement revealed that Toshiba's decision to consider a sale to a private buyer has progressed to the point at which discussions are under way with §0 parties who have expressed an interest in submitting a proposal to buy the company.

    Those talks have become sufficiently serious that Toshiba has appointed two sets of advisors – from Mizuho Securities and JP Morgan Securities – to offer financial advice and assist the special committee Toshiba assembled to consider offers.

    Continue reading

Biting the hand that feeds IT © 1998–2022