Washington: Cryptographers have demonstrated that even the most secure computers are vulnerable to attacks and the increasing popularity of cloud computing makes the threat even greater.

A savvy hacker can track information from the time a computer takes to store data in memory, fluctuations in its power consumption and even the noises it emits. Attacks that use such indirect sources of information are called side-channel attacks, and the increasing popularity of cloud computing makes them an even greater threat.

Fortunately, Shafi Goldwasser, professor of electrical engineering and computer science at Massachusetts Institute of Technology (MIT) and her former student Guy Rothblum, now with Microsoft Research, have worked out a way to mitigate such side-channel attacks, according to an MIT statement.

Besides preventing attacks on private information, Goldwasser says the technique could also protect devices that use proprietary algorithms so that they cannot be reverse-engineered by pirates or market competitors -- an application that she, Rothblum and others described at last year's AsiaCrypt conference.

According to Nigel Smart, a professor of cryptology in the computer science department at the University of Bristol in the UK, the danger of side-channel attacks "has been known since the late 1990s".

"There's a lot of engineering that was done to try to prevent this from being a problem," Smart says, "a huge amount of engineering work. This is a megabucks industry."

Much of that work, however, has relied on trial and error, Smart says. Goldwasser and Rothblum's study, on the other hand, "is a much more foundational study, looking at really foundational, deep questions about what is possible".

Smart cautions, however, that the work of Goldwasser and her colleagues is unlikely to yield practical applications in the near future.