  Our high expectations from Internet of Things (IoT) and how it will
positively influence our lifestyles depend on a secure and trusted
implementation of it, especially in the sensitive sectors such as health or
financial. IoT platforms and solutions must provide Confidentiality, Integrity
and Availability (CIA) in a secure and transparent way. Due to the extremely
large scales of IoT, traditional centralized solutions for security
provisioning cannot be employed in their original form. This article discusses
the authentication problem in IoT, which is fundamental to providing CIA. We
propose a hierarchical security architecture for this problem and focus on
computationally lightweight authentication protocols which can intelligently
distribute the computational load across multiple levels and effectively push
the load towards upper layers.
