# US 12,604,181 B2 · Subscription concealed identifier privacy

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- Number: US 12,604,181 B2
- Document ID: US12604181B2
- Status: Granted
- Kind: B2
- Application number: 17/771,539
- Filed: 2020-10-29
- Published: 2022-12-22
- Granted: 2026-04-14
- Earliest claimed: 2019-11-04
- Assignees: Telefonaktiebolaget LM Ericsson (publ)
- Applicants: Telefonaktiebolaget LM Ericsson (publ)
- Inventors: John Mattsson; Prajwol Kumar Nakarmi; Erik Thormarker
- Web page: https://patentgrep.com/patent/US12604181B2

## CPC

- H04W 12/02: Protecting privacy or anonymity, e.g. protecting personally identifiable information [PII]
- H04L 9/0825: {using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates}
- H04W 12/03: Protecting confidentiality, e.g. by encryption
- H04W 12/40: Security arrangements using identity modules
- H04W 12/72: Subscriber identity
- H04L 2209/42: Anonymization, e.g. involving pseudonyms
- H04L 2209/80: Wireless
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A user equipment (“UE”) in a wireless communication network can generate a padded identifier by inserting a padding bitstring in a field of an identifier associated with the UE. The UE can further encrypt the padded identifier to generate a concealed padded identifier. The UE can further transmit the concealed padded identifier to a network node operating in the wireless communication network.

## Claims

### Claim 1

A method of operating a user equipment (UE) in a wireless communication network, the method comprising:
generating a padded identifier by inserting a padding bitstring in a field of an identifier associated with the UE, wherein the identifier is a subscription permanent identifier (SUPI), wherein fields of the SUPI comprise at least one of: a mobile subscriber identification number (MSIN), a username, a routing identifier, a public key identifier, or a scheme identifier, wherein generating the padded identifier comprises padding at least one of: the MSIN, the username, the routing identifier, the public key identifier, or the scheme identifier, wherein generating the padded identifier comprises inserting a delimiter before or after the padding bitstring, the delimiter being a predetermined bitstring that separates the padding bitstring from unpadded content of the field of the identifier, wherein the delimiter comprises a first delimiter and a second delimiter, and wherein inserting the delimiter comprises inserting the first delimiter before the padding bitstring and inserting the second delimiter after the padding bitstring;
encrypting the padded identifier to generate a concealed padded identifier; and
transmitting the concealed padded identifier to a network node operating in the wireless communication network.

### Claim 2 (depends on 1)

The method of claim 1, wherein the UE comprises at least one of a universal subscriber identity module (USIM) and a mobile equipment (ME),
wherein the padding bitstring comprises one or more bits, and
wherein the concealed padded identifier is a subscription concealed identifier (SUCI).

### Claim 3 (depends on 1)

The method of claim 1, wherein transmitting the concealed padded identifier to the network node operating in the wireless communication network comprises transmitting the concealed padded identifier to the network node operating in the wireless communication network during operation by the UE for registration of the UE with the wireless communication network.

### Claim 4 (depends on 1)

The method of claim 1, further comprising receiving a request for the identifier from the network node,
wherein transmitting the concealed padded identifier to the network node operating in the wireless communication network comprises transmitting the concealed padded identifier to the network node operating in the wireless communication network in response to receiving the request from the network node.

### Claim 5 (depends on 1)

The method of claim 1, wherein generating the padded identifier comprises:
receiving padding instructions from the network node, the padding instructions indicating at least one of: a length, a content, or the delimiter usable by the UE to pad the identifier; and
padding the identifier based on the padding instructions.

### Claim 6 (depends on 1)

The method of claim 1, wherein generating the padded identifier comprises:
receiving padding instructions from a user of the UE via a user interface of the UE, the padding instructions indicating at least one of: a length, a content, or the delimiter usable by the UE to pad the identifier; and
padding the identifier based on the padding instructions.

### Claim 7 (depends on 1)

The method of claim 1, wherein the wireless communication network comprises a home network and a serving network and the network node comprises a home network node and a serving network node, and
wherein transmitting the concealed padded identifier to the network node comprises transmitting the concealed padded identifier to the serving network node to be partially decrypted and further transmitted by the serving network node to the home network node to be further decrypted.

### Claim 8

A method of operating a network node in a wireless communication network, the method comprising:
determining a padding technique usable by a user equipment (UE) in the wireless communication network to insert a padding bitstring in a field of an identifier associated with the UE prior to the UE encrypting the identifier, wherein the identifier is a subscription permanent identifier (SUPI), wherein fields of the SUPI comprise at least one of: a mobile subscriber identification number (MSIN), a username, a routing identifier, a public key identifier, or a scheme identifier, wherein the padding technique comprises padding at least one of: the MSIN, the username, the routing identifier, the public key identifier, or the scheme identifier, wherein the padding technique comprises inserting a delimiter before or after the padding bitstring, the delimiter being a predetermined bitstring that separates the padding bitstring from unpadded content of the field of the identifier, wherein the delimiter comprises a first delimiter and a second delimiter, and wherein inserting the delimiter comprises inserting the first delimiter before the padding bitstring and inserting the second delimiter after the padding bitstring;
receiving a concealed padded identifier from the UE;
decrypting the concealed padded identifier to generate a padded identifier; and
determining content of the identifier separate from the padding bitstring based on the padding technique.

### Claim 9 (depends on 8)

The method of claim 8, wherein the UE comprises at least one of a universal subscriber identity module (USIM) and a mobile equipment (ME),
wherein the padding bitstring comprises one or more bits,
and
wherein the concealed padded identifier is a subscription concealed identifier (SUCI).

### Claim 10 (depends on 8)

The method of claim 8, wherein determining the padding technique comprises determining the delimiter that is insertable before or after the padding bitstring, the delimiter being a predetermined bitstring that separates the padding bitstring from content of the identifier, and
wherein determining the content of the identifier comprises:
identifying the delimiter in the padded identifier; and
removing the delimiter and the padding bitstring before or after the delimiter.

### Claim 11 (depends on 8)

The method of claim 8, further comprising transmitting, responsive to determining the padding technique and prior to receiving the concealed padded identifier, padding instructions to the UE informing the UE of the padding technique.

### Claim 12 (depends on 8)

The method of claim 8, wherein determining the padding technique comprises receiving padding instructions informing the network node of the padding instructions usable by the UE.

### Claim 13 (depends on 8)

The method of claim 8, wherein receiving the concealed padded identifier from the UE comprises receiving the concealed padded identifier from the UE as part of a registration request by the UE to join the wireless communication network.

### Claim 14 (depends on 8)

The method of claim 8, further comprising transmitting a request to the UE for the identifier,
wherein receiving the concealed padded identifier from the UE comprises receiving the concealed padded identifier from the UE in response to transmitting the request to the UE.

### Claim 15

A user equipment (UE) operating in a wireless communication network comprising:
processing circuitry; and
memory coupled to the processing circuitry and having instructions stored therein that are executable by the processing circuitry to cause the UE to perform operations comprising:
generating a padded identifier by inserting a padding bitstring in a field of an identifier associated with the UE, wherein the identifier is a subscription permanent identifier (SUPI), wherein fields of the SUPI comprise at least one of: a mobile subscriber identification number (MSIN), a username, a routing identifier, a public key identifier, or a scheme identifier, wherein generating the padded identifier comprises padding at least one of: the MSIN, the username, the routing identifier, the public key identifier, or the scheme identifier, wherein generating the padded identifier comprises inserting a delimiter before or after the padding bitstring, the delimiter being a predetermined bitstring that separates the padding bitstring from unpadded content of the field of the identifier, wherein the delimiter comprises a first delimiter and a second delimiter, and wherein inserting the delimiter comprises inserting the first delimiter before the padding bitstring and inserting the second delimiter after the padding bitstring;
encrypting the padded identifier to generate a concealed padded identifier; and
transmitting the concealed padded identifier to a network node operating in the wireless communication network.

### Claim 16

A network node operating in a wireless communication network, the network node comprising:
processing circuitry; and
memory coupled to the processing circuitry having instructions stored therein that are executable by the processing circuitry to cause the network node to perform operations comprising:
determining a padding technique usable by a user equipment (UE) in the wireless communication network to insert a padding bitstring in a field of an identifier associated with the UE prior to the UE encrypting the identifier, wherein the identifier is a subscription permanent identifier (SUPI), wherein fields of the SUPI comprise at least one of: a mobile subscriber identification number (MSIN), a username, a routing identifier, a public key identifier, or a scheme identifier, wherein the padding technique comprises padding at least one of: the MSIN, the username, the routing identifier, the public key identifier, or the scheme identifier, wherein the padding technique comprises inserting a delimiter before or after the padding bitstring, the delimiter being a predetermined bitstring that separates the padding bitstring from unpadded content of the field of the identifier, wherein the delimiter comprises a first delimiter and a second delimiter, and wherein inserting the delimiter comprises inserting the first delimiter before the padding bitstring and inserting the second delimiter after the padding bitstring;
receiving a concealed padded identifier from the UE;
decrypting the concealed padded identifier to generate a padded identifier; and
determining content of the identifier separate from the padding bitstring based on the padding technique.