Schemes and methods of integrity protection in mobile communication

A method of a User Equipment (UE), the method comprising:

• sending, to a Radio Access Network (RAN) node, first security information for User Plane (UP) integrity protection;
• receiving, from the RAN node, second security information for the UP integrity protection, wherein the second security information is decided by the RAN node for security information negotiation;
• and
• generating a Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) including a PDCP header, data, and a Message Authentication Code-Integrity (MAC-I) using the second security information, wherein the PDCP header comprises at least one bit that indicates whether the integrity protection is used in the PDU or not.

A Radio Access Network (RAN) node, comprising:

• one or more memories configured to store instructions;
• and
• one or more processors configured to execute the instructions to:
• receive, from a User Equipment (UE), first security information for User Plane (UP) integrity protection,
• send, to the UE, second security information for the UP integrity protection, wherein the second security information is decided by the RAN node for security information negotiation, and
• generate a Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) including a PDCP header, data, and a Message Authentication Code-Integrity (MAC-I) using the second security information, wherein the PDCP header comprises at least one bit that indicates whether the integrity protection is used in the PDU or not.

A method of a Radio Access Network (RAN) node, comprising:

• receiving, from a User Equipment (UE), first security information for User Plane (UP) integrity protection;
• sending, to the UE, second security information for UP integrity protection, wherein the second security information is decided by the RAN node for security information negotiation;
• and
• generating a Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) including a PDCP header, data, and a Message Authentication Code-Integrity (MAC-I) using the second security information, wherein the PDCP header comprises at least one bit that indicates whether the integrity protection is used in the PDU or not.