Internet of Things (IoT) can be seen as a pervasive network of networks: numerous heterogeneous entities both physical and virtual interconnected with any other entity or entities through unique addressing schemes, interacting with each other to provide/request all kinds of services. IoT technology is expected to pave the way for groundbreaking applications in a diversity of areas such as healthcare, security and surveillance, transportation, and industry, and integrate advanced technologies of communication, networking, cloud computing, sensing and actuation. Given the enormous number of connected devices that are potentially vulnerable, highly significant risks emerge around the issues of security, privacy, and governance; calling into question the whole future of IoT. IoT applications are expected to affect many aspects of people's lives, bringing about many conveniences; however, if security and privacy cannot be ensured, this can lead to a number of undesired consequences. This survey focuses on the security aspects of IoT, and discusses up-to-date IoT security solutions.