It has been more than 20 years since the seminal publications on side-channel attacks. They aim at extracting secrets from embedded systems while they execute cryptographic algorithms, and they consist of two steps, measurement and analysis. This book tackles the analysis part, especially under situations where the targeted device is protected by random masking. The authors explain advances in the field and provide the reader with mathematical formalizations. They present all known analyses within the same notation framework, which allows the reader to rapidly understand and learn contrasting approaches. It will be useful as a graduate level introduction, also for self-study by researchers and professionals, and the examples are taken from real-world datasets.