International Association
for Cryptologic Research

Since their introduction over two decades ago, physical side-channel attacks have presented a serious security threat. While many ciphers’ implementations employ masking techniques to protect against such attacks, they often leak secret information due to unintended interactions in the hardware. We present Rosita, a code rewrite engine that eliminates such leakage. Rosita uses a leakage emulator which we amended to correctly emulate leakage from the target system and then rewrites the code to eliminate that leakage. We use Rosita to automatically protect masked implementations of AES and Xoodoo and show the absence of observable leakage at only a 25% penalty to the performance.