Systems, methods, and instrumentalities are provided for vehicle to everything (V2X) service oriented link establishment. A first wireless transmit receive unit (WTRU) may broadcast a direct communication request message. The direct communication request message may include a first security context identifier (ID). The first WTRU may receive a direct security mode command message from a second WTRU. The direct security mode command message may include a second security context ID. The first may determine a third security context ID by combining the first security context ID and the second security context ID. The first WTRU may establish, using the third security context ID, a secure direct communication link with the second WTRU. The first WTRU may generate, based on the third security context ID, a security context entry for the secure direct communication link with the second WTRU.