Embedded systems are devices used to control, monitor or assist the operation of a larger system they are embedded into. They are often controlled through the corresponding user interface. This thesis describes the development of a user interface for the Xiphra SE encryption devices which are produced and marketed by Beyond Semiconductor company. In the first part, the reader will be introduced to a handful of basic input/output devices and with the way they can be used inside the Linux system. Font smoothing methods are explained further on since they are quite often being used to increase readability of the displayed information. The mid-part talks about planning the development of user interfaces influenced by the understanding of specifics and limitations of embedded systems. With this in mind, a plan for the development of the Xiphra SE user interface is created, defining all our needs and requirements. It also evaluates existing solutions: two GUI frameworks and one widget library, which can be used to speed up the development process. In the main part, the thesis describes the creation of the development environment that consists of the following software components: framebuffer driver, font tool, framebuffer simulator, graphics library, widget library and graphical user interface for the Xiphra SE devices. In the last part, we sum up our work and give options for further improvements.