The chapter sheds light on Hamas’s signal intelligence (SIGINT) and cyber warfare. It describes how, in the first decade of the 2000s, Hamas gained SIGINT capabilities that made it possible for Hamas to intercept the camera broadcasts of IDF UAVs, as well as the IDF’s visible tactical communication traffic. In the 2010s, Hamas began to invest in cyber warfare. This chapter also surveys Hamas’s successful use of various hacking methods to penetrate the smartphones of IDF soldiers and officers, extracting information and installing spyware and using social engineering techniques; descriptions of several real-life cases are included for illustration.