Feedback Shift Register (FSR) based stream ciphers are known to be vulnerable to power analysis attacks due to their simple hardware structure. In this paper, we propose a countermeasure against non-invasive power analysis attacks based on switching activity masking. Our solution has a 50% smaller power overhead on average compared to the previous standard cell-based countermeasures. Its resistance against different types of attacks is evaluated on the example of Grain-80 stream cipher.
QC 20130930