Embodiments are directed to systems, methods and computer program products for enhancing proximity service (ProSe) device to device (D2D) discovery. Embodiments build a discovery message configured for communication over the MAC sub-layer; wherein the discovery message comprises a unified header comprising at least one of a priority level indicator for indicating a priority level of the discovery message; a security existence indicator for indicating whether the discovery message is at least partially encrypted; a type indicator for indicating a discovery message type; and/or an SDU presence indicator (S_ind) for indicating whether the discovery message includes an SDU.