This work presents KUCAS (Known User Continuous Authentication System), a work-in-progress security system, that has a continuous authentication mechanism of users in software application. The KUCAS system makes use of environmental context information, users behavior analysis, the behavior theories of Skinner and the Mathematical Confidence of Dempster-Shafer Evidences Theory, that establishes trust levels to authenticate the user by his behavior analysis, during an application software, in a specific domain of the computer networks, in a period of time. The dynamics of enclosed management in this system compares the current behavior with the user's previous behaviors description and with the trust restrictions. In case of indications of changes in the user's behavior, the system provides the behavior analysis of the user using database restrictions information. If there are uncertainties and divergences, mechanisms of security and alert signals are triggered.