Table of Contents Introduction Solving the Challenge Additional Thoughts Conclusion Introduction The hardest and also most interesting cryptography challenge of PicoCTF 2023 involved undoing AES using a side channel attack, specifically power analysis. If I’m going to be honest, it was a pretty big surprise to see a side channel attack be the primary challenge within Pico but it was definitely a fun experience. Solving the Challenge The core idea of correlation power analysis (CPA) is to take the non-linear part of AES, the S-box lookup and use that bit of info to extract more information about the key....