These days, processed data size has been increasing and has grown exponentially, that is, not only text data but especially multimedia data with visual and auditory information. Such data may be generated by humans but also by many sources and technical equipment including IoT (Internet of Things) nodes. Intelligent technologies developed for representing the natural way of human thinking have a semantic gap between low level and high level information processing stages. Many research studies for reducing semantic gaps are focused on the representation methods of various logics. Other approaches also used include artificial neural network, semantic web, knowledge engineering, and heuristic approaches among others, specially oriented for using computational intelligence approaches or cognitive technologies. 1 Having such enormous data, it is very important to introduce efficient analytics solutions allowing analysis, storage, and semantic processing of complex and Big Data and to perform management tasks in a secure manner toward guaranteeing security and confidentiality of data transmissions over global communication networks or mobile computing.Such intelligent approaches for security are one of the most important research areas because of the fast growing interest of intelligent processing method, which offer good opportunities for novel studies. Such systems use a semantic approach that could be applied to develop ontologies, an intelligent access control model, and context-aware detection of attacks. 2 In addition, advanced security technologies are the important issue because the attacks aiming have also been increased owing to the merit of being available anytime and anywhere.The possibility of development and application of such security technologies will depend on different factors such as the creation of new generation embedded systems or the application of innovative security models for users or peer communications, service managements, etc.These subjects and a number of others like the innovative and secure applications; the ways of using biometrics, vision, and cognitive approaches for security applications; secure communication protocols; and smart devices and services will form the subject of this Special Issue on "Intelligent Approaches for Security Technologies" in the Concurrency and Computation: Practice and Experience Journal.To this Special Issue, ten articles of the particular interest were selected, as they present the most interesting research studies within the subject matter of this special issue.The paper "User biometric information-based secure method for smart devices" by Xin et al 3 presented novel solutions for creating resistant and strong passwords for mobile subscribers. The authors described studies on potential security problems caused by simple and weak passwords and discussed some drawbacks of conventional solutions. Additionally, they introduced three creative schemes, which allow increasing the complexity and strength of passwords by applying the envisioned features. These ...