GRINCH - A Cache Attack against GIFT Lightweight Cipher.

The National Institute of Standard and Technology (NIST) has recently started a competition with the objective to standardize lightweight cryptography (LWC). The winning schemes will be deployed in Internet-of-Things (IoT) devices, a key step for the current and future information and communication technology market. GIFT is an efficient lightweight cipher and it is used by one-fourth of the LWC candidates in the NIST LWC competition. Thus, its security evaluation is critical. One vital threat to the security are so-called logical side-channel attacks based on cache observations. In this work, we propose a novel cache attack on GIFT referred to as GRINCH. We analyzed the vulnerabilities of GIFT and exploited them in our attack. The results show that the attack is effective and that the full key could be recovered with less than 400 encryptions.