Security is a growing concern in developing software systems. It is important to face unknown threats in order to make the system continue operating properly. Threats are vague and attack methods change frequently. Coping with such changes is a major feature of an adaptive software. Therefore, designing an adaptive secure software is an appropriate solution to address software security challenges. Through estimation of maximum amount of system assets security, one can determine whether the system is protecting the assets or not; if not, reconfiguration can be employed. This paper proposes a new requirement model for secure adaptive systems using fuzzy, goal modeling and Description Logic concepts. The model contains three phases of modeling security aspects of the system, identifying formalizations and relations between the requirements and monitoring and adapting, when needed. To illustrate the relations between the requirements, goal modeling is used in the first phase and fuzzy Description Logic in the second phase. For the third phase, four algorithms are proposed to monitor and determine whether reconfiguration is needed or not. Theorems are given to prove concept satisfaction of the requirements. Furthermore, examples and case studies are discussed to evaluate and show applicability of the proposed model.

In the real-world, there are many types of software systems and software engineers always deal with changes. The value of large systems decreases significantly as the requirements and operational environment change over time. Modern software systems are expected to have dynamic reconfigurations to cope with failure and changes. Software adaptation techniques try to overcome the change problem by reconfiguration. In this study, at first, the authors present a formal framework to represent the whole system and then, build a mathematical model called 'adaptor' based on adaptation contract and system architecture. The adaptor is used to define automatic fit between two different components of the system. Finally, for specifying the whole adaptor system the authors will introduce adaptor network using synchronisation vectors.