ROLL-OVER OF IDENTIFIERS AND KEYS FOR UNICAST VEHICLE TO VEHICLE COMMUNICATION LINKS
Methods, systems, and devices for wireless communications are described that improve privacy in wireless communications, such as communications by a user equipment (UE), which may in some cases be a vehicle UE. For example, various vehicle-to-everything (V2X) transmissions may be unencrypted, and a vehicle may be expected to periodically change one or more identifiers it uses for various communication services. Privacy may be enhanced, for example, via encryption key roll-over, as well as roll-over of one or more other identifiers associated with a UE that may potentially be used by an observer to track the UE. The UE may transmit a message that includes an updated lower layer identifier (e.g., a layer-2 (L2) identifier) to another UE in a V2X unicast communications link, which may trigger a change in identifiers of a set of identifiers and an updated security context. All or a portion of the message may be encrypted.
1 . A method for wireless communication, comprising:
establishing, at a first UE, a vehicle-to-everything (V2X) unicast communications link between the first UE and a second UE, wherein the first UE has a first set of identifiers associated with the V2X unicast communications link including a first layer-2 (L2) address;
transmitting, from the first UE to the second UE, a message including a second set of identifiers that is different than the first set of identifiers, the second set of identifiers including a second L2 address different from the first L2 address; and
communicating with the second UE via the V2X unicast communications link using the second set of identifiers.
2 . The method of claim 1 , wherein the message comprises a rekey request message.
3 . The method of claim 1 , wherein the message includes an encrypted first information element (IE) containing the second L2 address.
4 . The method of claim 3 , wherein the message further includes an encrypted second IE containing a second Internet Protocol (IP) address that is different than a first IP address of the first set of identifiers.
5 . The method of claim 1 , wherein the entire message is encrypted based on one or more of the first set of identifiers.
6 . The method of claim 1 , further comprising:
receiving, from the second UE, a response message, wherein the response message includes a new L2 address of the second UE that is different than a prior L2 address of the second UE.
7 . The method of claim 1 , wherein the transmitting the message comprises:
transmitting the message using the second L2 address, and wherein a message integrity check (MIC) of the message is based on one or more of the first set of identifiers.
8 . The method of claim 7 , wherein the MIC is computed based on a session key (K D-sess ), or on a key derived from the session key, for direct communications between the first UE and the second UE.
9 . The method of claim 1 , wherein the second L2 address is a source L2 address and the message further includes a destination L2 address of the second UE.
10 . The method of claim 1 , wherein the second set of identifiers include at least two identifiers that are different from corresponding identifiers of the first set of identifiers.
11 . The method of claim 1 , further comprising:
receiving, at the first UE from the second UE, a second message; and
communicating with the second UE using one or more updated identifiers of the second UE that are determined based at least in part on the second message.
12 . The method of claim 1 , wherein the first set of identifiers include:
one or more lower layer identifiers,
one or more security layer identifiers,
one or more network/transport layer identifiers,
one or more facility layer identifiers,
one or more application layer identifiers, or
any combinations thereof.
13 . The method of claim 12 , wherein the first set of identifiers further include one or more physical layer parameters, the one or more physical layer parameters including one or more of a physical layer resource allocation associated with the first UE or a semi-persistent scheduling (SPS) parameter associated with the first UE.
14 . The method of claim 12 , wherein:
the one or more lower layer identifiers include a medium access control (MAC) address or the first L2 address;
the one or more security layer identifiers include a temporary certificate;
the one or more network/transport layer identifiers include a geonetworking address;
the one or more facility layer identifiers include a station identifier or temporary identifier associated with a cooperative awareness message (CAM), decentralized environmental notification message (DENM), or basic safety message (BSM); and
the one or more application layer identifiers include a transport protocol ID or an application layer ID.
15 . A method for wireless communication, comprising:
establishing, at a second UE, a vehicle-to-everything (V2X) unicast communications link with a first UE, wherein the first UE has a first set of identifiers associated with the V2X unicast communications link including a first layer-2 (L2) address;
receiving, from the first UE, a message including a second set of identifiers that are different than the first set of identifiers, the second set of identifiers including a second L2 address different than the first L2 address; and
communicating with the first UE via the V2X unicast communications link using the second set of identifiers.
16 . The method of claim 15 , wherein the message comprises a rekey request message.
17 . The method of claim 15 , wherein the message includes an encrypted first information element (IE) containing the second L2 address.
18 . The method of claim 17 , wherein the message further includes an encrypted second IE containing a second Internet Protocol (IP) address that is different than a first IP address of the first set of identifiers.
19 . The method of claim 15 , wherein the entire message is encrypted based on one or more of the first set of identifiers.
20 . The method of claim 15 , further comprising:
transmitting, to the first UE, a response message, wherein the response message includes a new L2 address of the second UE that is different than a prior L2 address of the second UE.
21 . The method of claim 15 , wherein the receiving the message comprises:
receiving the message having the second L2 address; and
determining that the message is from the first UE based on a message integrity check (MIC) of the message, wherein the MIC of the message is based on one or more identifiers of the first set of identifiers.
22 . The method of claim 21 , wherein the MIC is computed based on a session key (K D-sess ), or on a key derived from the session key, for direct communications between the first UE and the second UE.
23 . The method of claim 15 , wherein the second L2 address is a source L2 address and the message further includes a destination L2 address of the second UE.
24 . The method of claim 15 , wherein the second set of identifiers include at least two identifiers that are different from corresponding identifiers of the first set of identifiers.
25 . The method of claim 15 , further comprising:
transmitting, to the first UE, a second message to update a third set of identifiers associated with the second UE; and
communicating with the first UE using a fourth set of identifiers that are determined based at least in part on the second message, wherein the fourth set of identifiers are different than the third set of identifiers.
26 . The method of claim 15 , wherein the first set of identifiers include:
one or more lower layer identifiers,
one or more security layer identifiers,
one or more network/transport layer identifiers,
one or more facility layer identifiers,
one or more application layer identifiers, or
any combinations thereof.
27 . The method of claim 26 , wherein the first set of identifiers further include one or more physical layer parameters, the one or more physical layer parameters including one or more of a physical layer resource allocation associated with the first UE or a semi-persistent scheduling (SPS) parameter associated with the first UE.
28 . The method of claim 26 , wherein:
the one or more lower layer identifiers include a medium access control (MAC) address;
the one or more security layer identifiers include a temporary certificate;
the one or more network/transport layer identifiers include a geonetworking address;
the one or more facility layer identifiers include a station identifier or temporary identifier associated with a cooperative awareness message (CAM), decentralized environmental notification message (DENM), or basic safety message (BSM); and
the one or more application layer identifiers include a transport protocol ID or an application layer ID.
29 . An apparatus for wireless communication, comprising:
a processor,
memory in electronic communication with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
establish, at a first UE, a vehicle-to-everything (V2X) unicast communications link between the first UE and a second UE, wherein the first UE has a first set of identifiers associated with the V2X unicast communications link including a first layer-2 (L2) address;
transmit, from the first UE to the second UE, a message including a second set of identifiers that is different than the first set of identifiers, the second set of identifiers including a second L2 address different from the first L2 address; and
communicate with the second UE via the V2X unicast communications link using the second set of identifiers.
30 . An apparatus for wireless communication, comprising:
a processor,
memory in electronic communication with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
establish, at a second UE, a vehicle-to-everything (V2X) unicast communications link with a first UE, wherein the first UE has a first set of identifiers associated with the V2X unicast communications link including a first layer-2 (L2) address;
receive, from the first UE, a message including a second set of identifiers that are different than the first set of identifiers, the second set of identifiers including a second L2 address different than the first L2 address; and
communicate with the first UE via the V2X unicast communications link using the second set of identifiers.