This Paper Proposes Andanalyzes a Behavior-Rule Specification-Based Technique For Intrusion Detectionof Medical Devices Embedded In a Medical Cyber Physical System (Mcps) In Whichthe Patient’S Safety Is of the Utmost Importance. a Methodology Is Proposed Totransform Behavior Rules to a State Machine, So That a Device That Is Beingmonitored For Its Behavior Can Easily Be Checked Against the Transformed Statemachine For Deviation from Its Behavior Specification. Using Vital Sign Monitormedical Devices As an Example; to Demonstrate the Intrusion Detection Techniquethat Can Effectively Trade False Positives Off For a High Detection Probabilityto Cope With More Sophisticated and Hidden Attackers to Support Ultra-Safe Andsecure Mcps Applications. Moreover, Through a Comparative Analysis, It Isdemonstrated That the Proposed Behavior-Rule Specification-Based Ids Techniqueoutperforms Two Existing Anomaly-Based Techniques For Detecting Abnormalpatient Behaviors In Pervasive Healthcare Applications.