A user equipment, UE, comprising: a wireless interface configured to communicate directly with a receiving UE using non-internet protocol, non-IP, communication by selecting a PC5 Signaling Protocol service data unit, SDU, type from an SDU type field in a packet data convergence protocol, PDCP, wherein the two UEs (902, 904) exchange data without prior layer-2 link establishment; memory configured to store instructions and data; and a processor configured to execute the instructions, the instructions causing the UE to: determine an identity of the receiving UE; encapsulate user data in a PC5 protocol message using a packet data convergence protocol, PDCP, data unit; provide an identifier that enables the receiving UE to extract the user data from the PC5 protocol message, wherein the identifier is an asserted identity, and wherein the asserted identity is digitally signed; and transmit the PC5 protocol message using a PC5 protocol, wherein to transmit the PC5 protocol message to the receiving UE further comprises to provide an encryption key and a key management server identifier, wherein the encryption key is used to encrypt the user data and wherein the encryption key is included in a Sakai-Kasahara Key Encryption, SAKKE, payload that is encoded using a public identity of the receiving UE and a key management server, KMS, public key. a wireless interface configured to communicate directly with a receiving UE using non-internet protocol, non-IP, communication by selecting a PC5 Signaling Protocol service data unit, SDU, type from an SDU type field in a packet data convergence protocol, PDCP, wherein the two UEs (902, 904) exchange data without prior layer-2 link establishment; memory configured to store instructions and data; and a processor configured to execute the instructions, the instructions causing the UE to: determine an identity of the receiving UE; encapsulate user data in a PC5 protocol message using a packet data convergence protocol, PDCP, data unit; provide an identifier that enables the receiving UE to extract the user data from the PC5 protocol message, wherein the identifier is an asserted identity, and wherein the asserted identity is digitally signed; and transmit the PC5 protocol message using a PC5 protocol, wherein to transmit the PC5 protocol message to the receiving UE further comprises to provide an encryption key and a key management server identifier, wherein the encryption key is used to encrypt the user data and wherein the encryption key is included in a Sakai-Kasahara Key Encryption, SAKKE, payload that is encoded using a public identity of the receiving UE and a key management server, KMS, public key. determine an identity of the receiving UE; encapsulate user data in a PC5 protocol message using a packet data convergence protocol, PDCP, data unit; provide an identifier that enables the receiving UE to extract the user data from the PC5 protocol message, wherein the identifier is an asserted identity, and wherein the asserted identity is digitally signed; and transmit the PC5 protocol message using a PC5 protocol, wherein to transmit the PC5 protocol message to the receiving UE further comprises to provide an encryption key and a key management server identifier, wherein the encryption key is used to encrypt the user data and wherein the encryption key is included in a Sakai-Kasahara Key Encryption, SAKKE, payload that is encoded using a public identity of the receiving UE and a key management server, KMS, public key.