With the ever-rising popularity of Internet of Things (IoT) devices, the issue of securing communication between the constrained nodes in the IoT network while still achieving adequate speed and performance is as significant as always. One of the protocols widely used for that purpose is the Constrained Application Protocol (CoAP). Designed as a lightweight and optimised version of Hypertext Transfer Protocol (HTTP), CoAP utilises the client/server REST architecture and runs on UDP. To secure communication, CoAP uses Datagram Transport Layer Security (DTLS) protocol. However, prior research and analysis of DTLS security mechanisms and performance overhead have shown that DTLS is yet to become the most efficient and secure protocol for IoT communication. At the beginning of 2020, a new protocol has emerged, which could potentially solve some of the CoAP/DTLS issues. WireGuard is a cryptographic encapsulation IP tunnel protocol initially designed to implement a minimal Virtual Private Network (VPN) into the Linux kernel. Similarly to DTLS, WireGuard runs on UDP; however, unlike DTLS, it is cryptographically opinionated, meaning that it utilises a fixed set of encryption algorithms. Furthermore, it presents some modifications which make the protocol more energy-efficient than its alternatives. This study explores the central security and performance requirements for IoT devices and summarises them in terms of Confidentiality, Integrity, Availability (CIA) triad. Furthermore, it presents CoAP in greater detail, followed by a presentation of DTLS and WireGuard. The fundamental part of the project is a comparative study between CoAP and CoAP over DTLS and WireGuard respectively. The reference implementations of the protocols are used to acquire the necessary data, and the experimental results are evaluated based on the criteria and attributes chosen beforehand. The results are further used to determine whether it could be beneficial to use WireGuard instead of DTLS.