Side-channel attacks, such as analyzing a processorapos;s electrical consumption or electromagnetic emissions, allow for the recovery of sensitive information, including cryptographic keys. These attacks are particularly effective and pose a serious threat to the security of embedded systems. This thesis focuses on combining low-impact software countermeasures to strengthen security against side-channel attacks, an idea that remains poorly explored in the current state of the art. The goal is to identify synergies and incompatibilities between these countermeasures to create more effective and lightweight solutions. In particular, low-entropy masking countermeasures will be considered. These ideas will be applied on cryptography algorithm, with a particular focus on post-quantum cryptography algorithms. The thesis aims to develop new ways to secure software, offering better trade-offs between security and performance than existing approaches.