Methods and apparatus for providing network-assisted key agreement for d2d communications

A method of communications, comprising:

• receiving a first non-access stratum (NAS) message, by a second user equipment (UE), which indicates a downlink count value and includes at least a portion of contextual information associated with communication with a first UE;
• sending a second NAS message;
• calculating a second UE key based on a MME-second UE key that is shared between the MME and the second UE, at least one of an uplink count value associated with the second NAS message or the downlink count value, and the at least a portion of the contextual information;
• and
• calculating a final UE key based at least on the second UE key.

A method of communications, comprising:

• receiving, by a mobility management entity (MME), a shared key request using a first non-access stratum (NAS) message, wherein the first NAS message indicates an uplink count value and includes at least a portion of contextual information associated with communication with a second UE;
• calculating a first UE key based on a MME-first UE key that is shared between the MME and a first UE, the uplink count value, and the at least a portion of the contextual information;
• receiving a message at least indicating successful contact with the second UE;
• and
• sending a second NAS message to the first UE at least indicating successful contact with the second UE.

An apparatus for wireless communication, comprising:

• means for sending, by a first user equipment (UE), a shared key request using a first non-access stratum (NAS) message to a mobility management entity (MME), wherein the first NAS message indicates an uplink count value and includes at least a portion of contextual information associated with communication with a second UE;
• means for calculating a first UE key based on a MME-first UE key that is shared between the MME and the first UE, the uplink count value, and the at least a portion of the contextual information;
• means for receiving a second NAS message from the MME;
• and
• means for calculating a final UE key based at least on the first UE key in response to reception of the second NAS message.

An apparatus for wireless communications, comprising:

• means for receiving a first non-access stratum (NAS) message, by a second user equipment (UE), which indicates a downlink count value and includes at least a portion of contextual information associated with communication with a first UE;
• means for sending a second NAS message;
• means for calculating a second UE key based on a MME-second UE key that is shared between the MME and the second UE, at least one of an uplink count value associated with the second NAS message or the downlink count value, and the at least a portion of the contextual information;
• and
• wherein the means for calculating is further configured to calculate a final UE key based at least on the second UE key.

An apparatus for communications, comprising:

• means for receiving, by a mobility management entity (MME), a shared key request using a first non-access stratum (NAS) message, wherein the first NAS message indicates an uplink count value and includes at least a portion of contextual information associated with communication with a second UE;
• means for calculating a first UE key based on a MME-first UE key that is shared between the MME and a first UE, the uplink count value, and the at least a portion of the contextual information;
• wherein the means for receiving is further configured to receive a message at least indicating successful contact with the second UE;
• and
• means for sending a second NAS message to the first UE at least indicating successful contact with the second UE.

An apparatus for wireless communication, comprising:

• a processing system configured to:
• send, by a first user equipment (UE), a shared key request using a first non-access stratum (NAS) message to a mobility management entity (MME), wherein the first NAS message indicates an uplink count value and includes at least a portion of contextual information associated with communication with a second UE;
• calculate a first UE key based on a MME-first UE key that is shared between the MME and the first UE, the uplink count value, and the at least a portion of the contextual information;
• receive a second NAS message from the MME;
• and
• calculate a final UE key based at least on the first UE key in response to reception of the second NAS message.

An apparatus for wireless communication, comprising:

• a processing system configured to:
• receive a first non-access stratum (NAS) message, by a second user equipment (UE), which indicates a downlink count value and includes at least a portion of contextual information associated with communication with a first UE;
• send a second NAS message;
• calculate a second UE key based on a MME-second UE key that is shared between the MME and the second UE, at least one of an uplink count value associated with the second NAS message or the downlink count value, and the at least a portion of the contextual information;
• and
• calculate a final UE key based at least on the second UE key.

An apparatus for wireless communication, comprising:

• a processing system configured to:
• receive, by a mobility management entity (MME), a shared key request using a first non-access stratum (NAS) message, wherein the first NAS message indicates an uplink count value and includes at least a portion of contextual information associated with communication with a second UE;
• calculate a first UE key based on a MME-first UE key that is shared between the MME and a first UE, the uplink count value, and the at least a portion of the contextual information;
• receive a message at least indicating successful contact with the second UE;
• and
• send a second NAS message to the first UE at least indicating successful contact with the second UE.

A computer program product, comprising:

• a computer-readable medium comprising code for:
• sending, by a first user equipment (UE), a shared key request using a first non-access stratum (NAS) message to a mobility management entity (MME), wherein the first NAS message indicates an uplink count value and includes at least a portion of contextual information associated with communication with a second UE;
• calculating a first UE key based on a MME-first UE key that is shared between the MME and the first UE, the uplink count value, and the at least a portion of the contextual information;
• receiving a second NAS message from the MME;
• and
• calculating a final UE key based at least on the first UE key in response to reception of the second NAS message.

A computer program product, comprising:

• a computer-readable medium comprising code for:
• receiving a first non-access stratum (NAS) message, by a second user equipment (UE), which indicates a downlink count value and includes at least a portion of contextual information associated with communication with a first UE;
• sending a second NAS message;
• calculating a second UE key based on a MME-second UE key that is shared between the MME and the second UE, at least one of an uplink count value associated with the second NAS message or the downlink count value, and the at least a portion of the contextual information;
• and
• calculating a final UE key based at least on the second UE key.

A computer program product, comprising:

• a computer-readable medium comprising code for:
• receiving, by a mobility management entity (MME), a shared key request using a first non-access stratum (NAS) message, wherein the first NAS message indicates an uplink count value and includes at least a portion of contextual information associated with communication with a second UE;
• calculating a first UE key based on a MME-first UE key that is shared between the MME and a first UE, the uplink count value, and the at least a portion of the contextual information;
• receiving a message at least indicating successful contact with the second UE;
• and
• sending a second NAS message to the first UE at least indicating successful contact with the second UE.