This document describes a cybersecurity evaluation methodology, named SESIP, for platforms and platform parts of connected IoT products. Security claims in SESIP are made based on the security services offered by those platforms. Platform parts can be in hardware and software. SESIP aims to support comparability between and reuse of independent security evaluations. SESIP provides a common set of requirements for the security functionality of platform parts which apply to the foundational platforms of devices that are not application specific. The methodology describes the re-use of evaluation results.