Slashdot Mirror
Stealing Keys From a Laptop In Another Room — and Offline
Motherboard carries a report that with equipment valued at about $3,000, a group of Israeli researchers have been able to extract cryptographic keys from a laptop that is not only separated by a physical wall, but protected by an air gap. This, they say, "is the first time such an approach has been used specifically against elliptic curve cryptography running on a PC." From the article:
The method is a so-called side-channel attack: an attack that doesn't tackle an encryption implementation head on, such as through brute force or by exploiting a weakness in the underlying algorithm, but through some other means. In this case, the attack relies on the electromagnetic outputs of the laptop that are emitted during the decryption process, which can then be used to work out the target's key.
Specifically, the researchers obtained the private key from a laptop running GnuPG, a popular implementation of OpenPGP. (The developers of GnuPG have since released countermeasures to the method. Tromer said that the changes make GnuPG âoemore resistant to side-channel attack since the sequence of high-level arithmetic operations does not depend on the secret key.â)
Tromer said that the changes make GnuPG Ãoemore resistant to side-channel attack since the sequence of high-level arithmetic operations does not depend on the secret key.Ã
Hey, speaking of character encoding on Slashdot...
- or -
Hey, use the "Preview" button!
Bonus funny: that changed from a lowercase 'a' with a '^' to an uppercase 'A' with a '~' while posting.
Dear Slashdot: next time you want to mess with the site, add a rich-text editor for comments.
In the case of laptops, it would add so much weight to do it right, that it would render them unfit for purpose. The problem is that shielding doesn't completely nix the EM emissions, but it removes a percentage. The trouble with that is that if someone has a sufficiently good antenna and low-noise amplifier, even a tiny fraction of the original EM emission could give you away, so standard anti-EM foil isn't going to cut it. For now, it's better to try to design our software in such a way that it emits the same EM signature regardless of the cryptographic key used.