  The widespread expansion of the IoT based services are changing peoples
living habits. With the vast data generation and intelligent decision support
system, an IoT is supporting many industries to improve their products and
services. The major challenge for IoT developers is to design a secure data
transmission system and a trustworthy inter device and user device
communication system. The data starts its journey from the sensing devices and
reaches the user dashboard through a different medium. Authentication between
two IoT devices provides a reliable and lightweight key generation system. In
this paper, we put forward a novel authentication approach for the IoT
paradigm. We postulate an ECC based two factor Level Dependent Authentication
for Generic IoT (LDA 2IoT) in which users at a particular level in the
hierarchy can access the sensors deployed at below or the equal level of the
hierarchy. We impart the security analysis for the proposed LDA 2IoT based on
the Dolev Yao channel and widely accepted random oracle based ROR model. We
provide the implementation of the proposed scheme using the MQTT protocol.
Finally, we set forth a performance analysis for the proposed LDA 2IoT system
by comparing it with the other existing scheme.
