Authorized access control to Smart Office With this final thesis a process of analysis, modeling and implementation of one IoT study case regarding the authorized access control to smart office is presented. First chapter presents a review of Internet of Things concepts, providing an explanation of such system's main requirements and benefits, mainly regarding the application in smart houses and offices. The analysis of abovementioned study case is described, as well as the abstract modeling of the solution backed up with the use-case, sequential and state diagrams. Also, a brief review about problems and inquiries of the security in IoT is presented. Furthermore, the work specifies the features and the configuration of the used ESP8266 Wi-Fi module as well as the tools and the programming languages which were used during the development process. Considering the upgrading nature of this project, which uses the existing access control system infrastructure, the applied upgrades and changes are shown (with the emphasis on the server side written in Java Spring Boot). Eventually, the insight into concrete implementation with the ESP8266 module is provided, including the short source code excerpts for actions of significant importance.