The ultimate adoption and success of context aware mobile communications lies in users understanding and accepting mobile services with regard to privacy, security, and trust. Security and privacy should an integral part of the mobility architectures. Contexts should be securely exchanged (authenticated and protected in terms of confidentiality and integrity) between context sources and context client. Context information as well as situations, triggers, and events information should also be securely stored and disseminated to prevent access from any malicious user and to protect user's privacy. IMAGINE Laboratory has an extensive experience in context awareness and its deployment in mobility management, together with policy management and automatic generation of policies from context information. These concepts and technologies are applied to implement policy based algorithms for the security and privacy of mobile users.