Encryption breakthrough: new way to generate random numbers
Encryption depends on random numbers, but generating random numbers is not easy; existing devices, which can typically only produce 10s or 100s of megabits of random numbers per second; researchers show new method that can generate truly random sequences at up to 1.7 gigabits per second
Random numbers are important for encryption, but generating them is not easy. New Scientist reports that a new method that uses lasers to produce streams of truly random numbers faster than ever before could help improve security at a time when both digital traffic and cyber crime are growing.
Strings of random numbers are used to make secret keys and other parts of encryption protocols. Software that generates random numbers, however, can typically manage only a close approximation to random. Statistical analysis reveals underlying if near-invisible patterns which means that an attacker could predict the sequence and break the code. Innovative ideas like tuning into atmospheric noise are sometimes used instead to achieve true chance, but now a new trick using the semiconductor lasers that power fiber-optic links offers a more practical way to improve security.
The new system is said to be able to generate truly random numbers 10 times faster than existing devices, which can typically only produce 10s or 100s of megabits of random numbers per second, says Atsushi Uchida, an electrical engineer at Saitama University, Japan. Uchida and colleague Peter Davis, from NTT Communication Science Laboratories in Kyoto, can now generate truly random sequences at up to 1.7 gigabits per second. They took a standard semiconductor laser and added an external mirror to reflect some of the light back inside the laser. That feedback causes the light produced to oscillate randomly. This can be converted into an AC current and then into a binary signal that can be used by a computer.
Signals from two lasers are combined into a single, truly random number sequence. Relatively inexpensive versions of the system could be built into cryptographic systems for secure network links, or quantum communication systems, say the researchers.
-read more in Atsushi Uchida et al., “Fast Physical Random Bit Generation with Chaotic Semiconductor Lasers,” Nature Photonics (23 November 2008) (doi:10.1038/nphoton.2008.227) (sub. req.)
