The discussion centers on a specific step in the RSA encryption proof, particularly focusing on the implications of equation 5 from the referenced paper. It clarifies that the relationship \( ed \equiv 1 \mod \phi(n) \) leads to the conclusion that \( \phi(n) \) divides \( ed - 1 \). This division implies that there exists an integer \( k \) such that \( ed \) can be expressed as \( \phi(n) \cdot k + 1 \). Consequently, this formulation allows for the equivalence \( M^{\phi(n) \cdot k + 1} = M^{ed} \). Understanding this step is crucial for grasping the foundational principles of RSA encryption.