Internet of Things (IoT) is an extensive and rapidly growing technology in this modern era. Due to its networking nature and rapid implementation in various fields, security is considered a primary challenge. Due to various security vulnerabilities, IoT infrastructure is prone to numerous security threats which in return affecting the IoT infrastructure on a wider scale. This paper proposes a stronger and robust, three-way security framework which is based on Public Key Infrastructure (PKI) certification mechanism. This framework represents a unique way to authenticate both, IoT device and user using digital certificates before granting them access into the system.