The information age is a time when organizations are networked back and forth with multiple wires, different communication channels, many sophisticated information systems, and most importantly through the almighty Internet. This project focuses on responses that are most beneficial to organizations in regards to the internal threats. Mainly, it addresses the issues connected to the broad use of laptops, desktops, and other personal devices such as flash drives. During research there were thought different ways of mitigating the issue of insider threats. The result of this analysis is the Diamond Theory. It ties four methods of increasing the security of personal devices: software design, information retrieval, detection technology design and information policy design. All four corners of the diamond are represented by four different techniques that increase the security of personal devices and thus the defense against insider threats. These techniques are described as theoretical premises that shall be fulfilled in order to have the security raised to the maximum. Additionally, these methods are interdependent of each other and must work together to meet the overall goal of the theory.