ANN ARBOR, Mich.—The most common digital security technique used to protect both media copyright and Internet communications has a major weakness, University of Michigan computer scientists have discovered.
Since 1977, RSA public-key encryption has protected privacy and verified authenticity when using computers, gadgets and web browsers around the globe, with only the most brutish of brute force efforts (and 1,500 years of processing time) felling its 768-bit variety earlier this year. Now, three eggheads (or Wolverines, as it were) at the University of Michigan claim they can break it simply by tweaking a device’s power supply. By fluctuating the voltage to the CPU such that it generated a single hardware error per clock cycle, they found that they could cause the server to flip single bits of the private key at a time, allowing them to slowly piece together the password. With a small cluster of 81 Pentium 4 chips and 104 hours of processing time, they were able to successfully hack 1024-bit encryption in OpenSSL on a SPARC-based system, without damaging the computer, leaving a single trace or ending human life as we know it. That’s why they’re presenting a paper at the Design, Automation and Test conference this week in Europe, and that’s why — until RSA hopefully fixes the flaw — you should keep a close eye on your server room’s power supply.
The RSA algorithm gives security under the assumption that as long as the private key is private, you can’t break in unless you guess it. We’ve shown that that’s not true," said Valeria Bertacco, an associate professor in the Department of Electrical Engineering and Computer Science.
These private keys contain more than 1,000 digits of binary code. To guess a number that large would take longer than the age of the universe, Pellegrini said. Using their voltage tweaking scheme, the University of Michagan researchers were able to extract the private key in approximately 100 hours.