An ambient Assisted Living (AAL) system can provide healthcare monitoring and e-health services. Assisted living promotes independence and dignity (aging in place) while reducing medical costs. Smart Homes equipped with several acoustic, vibration and vision-based sensors can help monitor patient activity and lifestyle. Since the information transmitted in AAL systems is very personal, the security and privacy of such data are important issues. Thus, information exchange needs to satisfy confidentiality, integrity, and availability requirements.