Chip Malfunctions Reveal Private Keys

By Robert Vamosi | 7/30/12 5:27 AM

Key leakage via side channel attacks, were the attacker "listens" to fluctuations in voltage as the encryption takes place, is well known. Recently, German researchers found that a faulty processor might also leak secrets during encryption. Known as transient faults, these were considered hard to produce … until now.

At last week's Black Hat Briefing in Las Vegas, Valeria Bertacco, associate professor of electrical engineering and computer science at University of Michigan and her team, found a way to produce transient faults on Linux servers they built running an Open SSL library and RSA encryption. The team found several ways for the server to fail: by altering the voltage; by changing the temperature of the chips; by over-clocking (it shortens the time to traverse the logic cloud); and natural particles that change internal signals. She demonstrated these adverse conditions on a Leon3 SPARC system using OpenSSL 0.9.8i ’s fixed Window Exponentiation algorithm.

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