How encryption keys could be stolen by your lunch

A device, hidden in pita bread, can collect signals that can betray encryption keys

A compact, inexpensive device that can collect a computer's electromagnetic signals could be hidden in a piece of pita bread and used to figure out secret encryption keys.

A compact, inexpensive device that can collect a computer's electromagnetic signals could be hidden in a piece of pita bread and used to figure out secret encryption keys.

Israel-based researchers said they've developed a cheaper and faster method to pull the encryption keys stored on a computer using an unlikely accomplice: pita bread.

The new study builds on research into what can be learned from the electronic signals that waft from computers while performing computations, often referred to as side-channel attacks.

By studying the electronic signals, researchers have shown it is possible to deduce keystrokes, figure out what application a person is using or discover the secret encryption keys used to encrypt files or emails.

This latest work focuses on capturing the encryption keys for laptops running GnuPG 1.x, an open source encryption program using the RSA and ElGamal key encryption algorithms. The researchers said they've notified the developer of GnuPG, Werner Koch, of their research.

The researchers built a device that could be concealed in pita bread that collects electromagnetic signals from 50 centimeters away.

They dubbed the device PITA, which stands for Portable Instrument for Trace Acquisition. It consists of a copper unshielded loop antenna with a capacitor designed to pick up frequencies around the 1.7MHz range at which encryption key information leaks.

With the signals collected on an internal microSD card, offline analysis can then be used to deduce the keys in just a few seconds.

As part of the attack, the PITA device sends a few carefully-crafted ciphertexts, or encrypted content, to a computer. When the content is decrypted by a computer, it gives off observable electromagnetic signals.

"The secret key can be deduced from these fluctuations, through signal processing and cryptanalysis," they wrote.

The researchers also built a second device to collect the signals. Since the 1.7MHz frequency is in the same range as AM radio, they used a commercial-grade radio receiver called the Road Master.

"We then recorded the signal by connecting it to the microphone input of an HTC EVO 4G smartphone," they wrote.

It's hard to defend against these kinds of side-channel attacks aside from making sure any suspicious aluminum foil packages containing pita bread are checked for electronic devices.

However, electromagnetic signals can be blocked using Faraday cages, which are enclosures that use metal to dissipate electronic signals. Few people, however, work in windowless metal boxes. PC manufacturers are also unlikely to address the problem in their hardware since it's just too expensive.

Re-engineering the software is a better approach. Algorithms and software could be changed to ensure the leaked signals are not distributing useful information. Work is already under way to make such changes, the researchers wrote.

"In fact, side-channel resistance of software implementations is nowadays a major concern," the paper said.

The paper was co-authored by Lev Pachmanov, Itamar Pipman and Era Tromer, all of Tel Aviv University; and Daniel Genkin who is associated with both the university and Technion. It will be presented at the Workshop on Cryptographic Hardware and Embedded Systems in Saint-Malo, France, in September.

Send news tips and comments to jeremy_kirk@idg.com. Follow me on Twitter: @jeremy_kirk

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags securityencryptionTechnionTel Aviv University

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Jeremy Kirk

IDG News Service
Show Comments

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Emily Tyson

MSI GE63 Raider

If you’re looking to invest in your next work horse laptop for work or home use, you can’t go wrong with the MSI GE63.

Laura Johnston

MSI GS65 Stealth Thin

If you can afford the price tag, it is well worth the money. It out performs any other laptop I have tried for gaming, and the transportable design and incredible display also make it ideal for work.

Andrew Teoh

Brother MFC-L9570CDW Multifunction Printer

Touch screen visibility and operation was great and easy to navigate. Each menu and sub-menu was in an understandable order and category

Louise Coady

Brother MFC-L9570CDW Multifunction Printer

The printer was convenient, produced clear and vibrant images and was very easy to use

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?