This deliverable (D2.4) of the 5G-ENSURE project describes a draft security architecture for 5G networks. The focus lies on a logical and functional architecture and omits (most) aspects related to physical/deployment architecture. This focus is motivated by general trends such as network de-perimetrization as well as 5G systems’ strong dependency on software defined networking and virtualization in general. Furthermore, this focus has reduced the otherwise strong interdependency between this architecture task and the trust modelling and risk analysis tasks in 5G-ENSURE. Still, each of these three tasks have at the time of writing produced initial draft documents, which will then be re-used in a second iteration of all three tasks, producing updated, final versions