The Internet of Things (IoT) is the extension of the internet to the physical world where all objects collect information and interact with their environments with no or little human intervention. They collect and transfer sensitive and private data from various users. This puts security and privacy issues at the forefront: the ability to manage the digital identity of millions of people and billions of devices is fundamental for success. As most of the information contained in IoT environment may be personal or sensitive data, there is a requirement to support anonymity and restrain access to information. This article will focus on access control and authentication mechanisms as well as supporting the cryptography algorithms in constrained devices.