EnGarde: Protecting the mobile phone from malicious NFC interactions

J. Gummeson, B. Priyantha, D. Ganesan, D. Thrasher, and P. Zhang


Near Field Communication (NFC) on mobile phones presents

new opportunities and threats. While NFC is radically changing

how we pay for merchandise, it opens a pandora’s box

of ways in which it may be misused by unscrupulous individuals.

This could include malicious NFC tags that seek

to compromise a mobile phone, malicious readers that try to

generate fake mobile payment transactions or steal valuable

financial information, and others. In this work, we look at

how to protect mobile phones from these threats while not

being vulnerable to them. We design a small form-factor

“patch", EnGarde, that can be stuck on the back of a phone

to provide the capability to jam malicious interactions. En-

Garde is entirely passive and harvests power through the

same NFC source that it guards, which makes our hardware

design minimalist and facilitating eventual integration with

a phone. We tackle key technical challenges in this design

including operating across a range of NFC protocols, jamming

at extremely low power, harvesting sufficient power

for perpetual operation while having minimal impact on the

phone’s battery, designing an intelligent jammer that blocks

only when specific blacklisted behavior is detected, and importantly,

the ability to do all this without compromising

user experience when the phone interacts with a legitimate

external NFC device.


Publication typeInproceedings
PublisherACM International Conference in Mobile Systems, Applications, and Services (MobiSys)
> Publications > EnGarde: Protecting the mobile phone from malicious NFC interactions