Operation related to user equipment using secret identifier

A method performed by a network node of a serving public land mobile network (PLMN) associated with a user equipment (UE), the method comprising:

• receiving, from the UE, a public identifier or a pseudonym corresponding to the UE;
• forwarding to a home PLMN of the UE the public identifier or pseudonym corresponding to the UE;
• receiving from the home PLMN an IMSI in response to the forwarding of the public identifier and or pseudonym, wherein the IMSI uniquely identifies the UE and is a secret that is shared between the UE and at least a home PLMN;
• and
• performing an operation related to a lawful interception of the UE using the IMSI.

A method performed by a network node of a home public land mobile network (PLMN) associated with a user equipment (UE), the method comprising:

• receiving a public identifier or pseudonym of the UE forwarded to the home PLMN by a serving PLMN of the UE;
• successfully authenticating the UE based on at least the public identifier or pseudonym,
• determining, upon successful authentication of the UE, to reveal to the serving PLMN, an ISMI that uniquely identifies the UE and is a secret that is shared between the UE and at least the home PLMN;
• revealing the IMSI to the serving PLMN, the IMSI allowing the serving PLMN to perform an operation related to a lawful interception of the UE using the IMSI.

A network node of a serving public land mobile network (PLMN) associated with a user equipment (UE), the network node comprising:

• a processor;
• and
• a memory, the memory containing instructions executable by the processor wherein the network node is configured to:
• receive, from the UE, a public identifier or a pseudonym corresponding to the UE;
• forward the public identifier or pseudonym to a home PLMN of the UE;
• receive from the home PLMN an IMSI in response to the forwarding of the public identifier or pseudonym, wherein the IMSI uniquely identifies the UE and is a secret that is shared between the UE and at least the home PLMN;
• and
• perform an operation related to a lawful interception of the UE using the IMSI.

A network node of a home public land mobile network (PLMN) associated with a user equipment (UE), the network node comprising:

• a processor;
• and
• a memory, the memory containing instructions executable by the processor wherein the network node is configured to:
• receive a public identifier or pseudonym of the UE forwarded to the home PLMN by a serving PLMN of the UE;
• successfully authenticate the UE based on at least the public identifier or pseudonym;
• determine, upon successful authentication of the UE, to reveal to the serving PLMN, an IMSI that uniquely identifies the UE and is a secret that is shared between the UE and at least the home PLMN;
• and
• reveal the IMSI to the serving PLMN, the IMSI allowing the serving PLMN to perform an operation related to a lawful interception of the UE using the IMSI.

A method performed by a serving public land mobile network (PLMN) associated with a user equipment (UE), the method comprising:

• receiving, from the UE, a public identifier or a pseudonym corresponding to the UE;
• forwarding to a home PLMN of the UE the received public identifier or pseudonym;
• receiving, from a home PLMN of the UE after the UE has been successfully authenticated by the home PLMN or the serving PLMN, an IMSI that uniquely identifies the UE and is a secret previously shared between the UE and the home PLMN;
• and
• performing a lawful interception related to the UE.

A method performed by a home public land mobile network (PLMN) associated with a user equipment (UE), the method comprising:

• receiving a public identifier or pseudonym of the UE forwarded to the home PLMN by a serving PLMN of the UE;
• successfully authenticating the UE based on at least the public identifier or pseudonym;
• determining to reveal, to a serving PLMN of the UE, an IMSI that uniquely identifies the UE and is a secret that is shared between the UE and the home PLMN;
• and
• revealing the IMSI to the serving PLMN after the UE has been successfully authenticated by the home PLMN or the serving PLMN, the IMSI allowing the serving PLMN to perform a lawful interception related to the UE.