The present document specifies the use of the mechanisms of IEEE 1609.2 [1] within the ITS communications architecture defined in EN 302 665 [3] to provide a stage 3 implementation for a subset of the security services defined in TS 102 731 [2]. The present document identifies: ? Those areas where IEEE 1609.2 [1] provides a security service defined in TS 102 731 [2]. ? Those areas where IEEE 1609.2 [1] needs to be extended or modified in a minor way to provide security services defined in TS 102 731 [2] and suitable for CAM and DENM. ? Those areas where IEEE 1609.2 [1] does not provide a basis for a security service defined in TS 102 731 [2] and consumed by CAM and DENM. In those cases where IEEE 1609.2 [1] does not fully provide a required service@ the present document identifies the requirements for that service but does not specify that service in full. The present document should therefore be seen not as a full specification of security for CAM and DENM but as a subset of that specification.