###### August 20, 2012

# New Quantum Computers Could Change Cyber Security For The Better

**Michael Harper for redOrbit.com — Your Universe Online**

Some of us were born naturally inclined to understand numbers and their relationships to one another. The rest of us, sadly, depend on the work of these mathematically savvy individuals just to function in everyday life. As such, while some may have no issues understanding prime numbers and calculating them in their heads, others may get a headache once they count past 10.

There are computers that exist, of course, which can handle the task of computing these sorts of numbers. While basic prime factors are a relatively easy task for them, the process becomes increasingly difficult for these computers when these factors contain more than 600 digits, taking these machines quite a long time to come to a solution.

In an attempt to make this process less challenging and less time-consuming, some UC Santa Barbara researchers have created a new quantum processor which can factor composite numbers, specifically the number 15 into the prime factors 3 and 5. Though 15 is a much smaller number than a 600 digit number, this latest development in calculation represents a turning point in making a quantum computer which will one day be able to factor much larger numbers. These new quantum computers could also offer significant implications in the battle against cybercrime, as well as further the field of cryptography.

The results of this study were published in an advance online edition of the journal Nature Physics.

“Fifteen is a small number, but what´s important is we´ve shown that we can run a version of Peter Shor´s prime factoring algorithm on a solid state quantum processor. This is really exciting and has never been done before,” said the paper´s lead author Erik Lucero, according to a prepared statement by the university.

Lucero was a doctoral student in physics at UCSB when the research was conducted and the paper was written. Now, he is a postdoctoral researcher in experimental quantum computing at IBM.

What will be most important in bringing this small development to a larger scale is keeping parity between this research and future implementation, says Andrew Cleland, a professor of physics at UCSB.

“What is important is that the concepts used in factoring this small number remain the same when factoring much larger numbers,” said Cleland, who collaborated with Lucero on this research.

“We just need to scale up the size of this processor to something much larger. This won´t be easy, but the path forward is clear.”

The ability to factor such large numbers is at the heart of cyber security protocols, said Lucero. Therefore, he wanted to conduct this research in order to improve on the existing cyber security protocols.

“Anytime you send a secure transmission, like your credit card information, you are relying on security that is based on the fact that it´s really hard to find the prime factors of large numbers,” said Lucero.

For example, a classical computer running a classical algorithm could take longer than the age of the universe to successfully factor the RSA Laboratory´s largest published number. This number, by the way, contains over 600 decimal digits. A quantum computer, similar to the one they´ve built ,could perform the same task in under an hour.

“A quantum computer can solve this problem faster than a classical computer by about 15 orders of magnitude,” said Lucero.

“This has widespread effect. A quantum computer will be a game changer in a lot of ways, and certainly with respect to computer security.”

**Image 2 (below): The device in the photomicrograph was used to run the first solid-state demonstration of Shor's algorithm. It is made up of four phase qubits and five superconducting resonators, for a total of nine engineered quantum elements. The quantum processor measures one-quarter inch square. Credit: UCSB**