e-commerce can be seen from different points of view. Its fields are always facing new challenges, variable conditions, evolving requirements, and thus new improvements are constantly demanded. Therefore, the importance for a usable and secure e-commerce website structure is more than necessary nowadays. In this paper we propose a requirements taxonomy consisting of the factors of security, usability, as well as characteristics for B2C and C2C e-commerce websites. The purpose of the taxonomy is to support the development of usable and secure B2C or C2C e-commerce websites. We also propose an evaluation approach for the stages of user interface design, architectural design, and testing with respect to taxonomy-based requirements.