# US 2019/0174307 A1 · Privacy preserving authentication and key agreement protocol for apparatus-to-apparatus communication

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- Number: US 2019/0174307 A1
- Document ID: US20190174307A1
- Status: Published application
- Kind: A1
- Application number: 16/323,204
- Filed: 2016-08-05
- Published: 2019-06-06
- Earliest claimed: 2016-08-05
- Assignees: Nokia Technologies Oy
- Applicants: Nokia Technologies Oy
- Inventors: Mingjun Wang; Zheng Yan
- Web page: https://patentgrep.com/patent/US20190174307A1

## CPC

- H04L 9/006: {involving public key infrastructure [PKI] trust models (network architecture or network communication protocol for supporting authentication of entities using certificates in a packet data network H04L63/0823)}
- H04L 9/0643: {Hash functions, e.g. MD5, SHA, HMAC or f9 MAC}
- H04L 9/0833: {involving conference or group key (network architectures or network communication protocols for key management in group communication in a packet data network H04L63/065)}
- H04L 9/0844: {with user authentication or key authentication, e.g. ElGamal, MTI, MQV-Menezes-Qu-Vanstone protocol or Diffie-Hellman protocols using implicitly-certified keys}
- H04L 9/0866: {involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics}
- H04L 9/0891: {Revocation or update of secret information, e.g. encryption key update or rekeying}
- H04L 63/0421: {Anonymous communication, i.e. the party's identifiers are hidden from the other party or parties, e.g. using an anonymizer}
- H04L 63/065: {for group communications (cryptographic mechanisms or cryptographic arrangements for key management involving conference or group key H04L9/0833)}
- H04L 63/067: {using one-time keys (cryptographic mechanisms or cryptographic arrangements for generation of one-time passwords H04L9/0863)}
- H04W 12/02: Protecting privacy or anonymity, e.g. protecting personally identifiable information [PII]
- H04W 12/04: Key management, e.g. using generic bootstrapping architecture [GBA]
- H04W 12/041: Key generation or derivation
- H04W 12/047: without using a trusted network node as an anchor
- H04W 12/0471: Key exchange
- H04W 12/50: Secure pairing of devices
- H04W 12/71: Hardware identity
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A method is disclosed, comprising obtaining, by a first apparatus, a first identifier associated with the first apparatus, wherein the first identifier is different from a second identifier associated with the first apparatus, providing, by the first apparatus, at least one message to at least one further apparatus of at least one further apparatus, wherein each of the at least one message comprises a key information of the first apparatus and is associated with the first identifier associated with the first apparatus, and determining, by the first apparatus, a session key of a communication session associated with the first apparatus and the at least one further apparatus, based on at least one message received, by the first apparatus, provided by at least one further apparatus of the at least one further apparatus, wherein each of the at least one message comprises a key information of the respective further apparatus and is associated with a first identifier associated with the respective further apparatus.

## Claims

### Claim 1

An apparatus comprising:
at least one processor; and
at least one memory including computer program code;
the at least one memory and the computer program code configured to, with the at least
one processor, cause the apparatus at least to perform:
obtain a first identifier associated with the apparatus, wherein the first identifier is different from a second identifier associated with the apparatus;
provide one or more messages to at least one further apparatus of a set of one or more apparatuses, wherein each of the one or more messages comprises key information of the apparatus and is associated with the first identifier associated with the apparatus; and
determine a session key of a communication session associated with the apparatus and at least one further apparatus, based on one or more messages received from at least one further apparatus of the set of one or more apparatuses, wherein each of the messages comprises key information of the respective further apparatus and is associated with a first identifier associated with the respective further apparatus.

### Claim 2 (depends on 1)

The apparatus according to claim 1, wherein the apparatus is associated with a public key, wherein the public key can be determined based on the first identifier associated with the apparatus and a first hash function.

### Claim 3 (depends on 2)

The apparatus according to claim 2, wherein the apparatus is further configured to perform for each message of at least one message of the one or more messages provided to at least one further apparatus of the set of one or more apparatuses:
determine a hash value based on the respective message and a second hash function;
determine a signature based on the hash value, the public key and a private key associated with the apparatus; and
provide the signature to the further apparatus associated with the respective message.

### Claim 4 (depends on 1)

The apparatus according to claim 1, wherein the apparatus is further configured to verify each message of at least one message of the one or more received message.

### Claim 5 (depends on 4)

The apparatus according to claim 4, wherein said verifying comprises:
determine a hash value based on the respective message and a second hash function; and
verify the respective message based on a signature associated with the message and based on the hash value and a public key associated with the further apparatus associated with the message; wherein the public key can be determined based on the first identifier associated with the apparatus and a first hash function.

### Claim 6 (depends on 1)

The apparatus according to claim 1, wherein the apparatus is further configured to perform determining a first key hint, wherein the key information of a first message of the one or more messages by the apparatus comprises said first key hint.

### Claim 7

(canceled)

### Claim 8 (depends on 1)

The apparatus according to claim 1, wherein a first received message of the one or more messages comprises a first key hint of the further apparatus associated with the first received message.

### Claim 9

(canceled)

### Claim 10 (depends on 8)

The apparatus of claim 8, wherein the apparatus is further configured to determine a first key based on the first key hint of the further apparatus associated with the first received message, and, optionally, a second key based on the first key hint of the further apparatus associated with the second received message.

### Claim 11 (depends on 8)

The apparatus according to claim 8, wherein the apparatus is further configured to determine, based on the first key hint of the first received message, and, optionally, based on the first key hint of the second received message, a second key hint.

### Claim at position 12

-13. (canceled)

### Claim 14 (depends on 1)

The apparatus of claim 1, wherein said one or more messages received by the apparatus are a plurality of received messages, wherein at least one message of the plurality of received messages comprises at least one second key hint associated with at least one further apparatus of the set of one or more apparatuses.

### Claim at position 14

-17. (canceled)

### Claim 18 (depends on 1)

The apparatus of claim 1, wherein the apparatus is further configured to receive information provided by a central network instance, the information comprising at least one of:
the first identifier associated with the apparatus, and/or
a first hash function, and/or
a second hash function, and/or
a third hash function, and/or
a generator g, and/or
a function e associated with bilinear pairing, and/or
a systems public key, and/or
a public key associated with the apparatus, wherein the public key can be determined based on the first hash function and the first identifier associated with the apparatus, and/or
a private key associated with the apparatus corresponding to the public key associated with the apparatus,
provided by the central network instance.

### Claim at position 16

-22. (canceled)

### Claim 23 (depends on 1)

The apparatus of claim 1, wherein the apparatus is further configured to perform: communicate securely with one or more apparatuses of the at least one further apparatus during the communication session based on the determined session key, wherein the apparatus and the at least one further apparatus represent a group associated with the communication session; and revoke the group based on at least one of an expiration date associated with the session key of the communication session, and/or a change of membership in the group, wherein said revoking the group comprises determining a new session key.

### Claim at position 18

-29. (canceled)

### Claim 30 (depends on 23)

The apparatus of claim 23, wherein the apparatus is further configured to perform the following, if the expiration date associated with the session key is expired and there are changes of the membership in the group:
provide one or more messages to at least one further apparatus of the set of one or more apparatuses, wherein each of the one or more messages comprises key information of the apparatus and is associated with the first identifier associated with the apparatus; and
determine the new session key of the communication session associated with the apparatus and the at least one further apparatus, based on one or messages received from at least one further apparatus of the set of one or more apparatuses, wherein each of the one or more messages comprises key information of the respective further apparatus and is associated with a first identifier associated with the respective further apparatus, wherein the apparatus and the at least one further apparatus are members of the group after the membership in the group has changed.

### Claim at position 20

-38. (canceled)

### Claim 39

A central network instance comprising:
at least one processor; and
at least one memory including computer program code;
the at least one memory and the computer program code configured to, with the at least
one processor, cause the central network instance at least to perform:
receive a second identifier of an apparatus of a set of apparatuses, the apparatuses of the set of apparatuses being associated with a communication session;
determine a first identifier associated with the apparatus, wherein this apparatus is associated with the second identifier;
determine a private key associated with the apparatus; and
provide information to the apparatus comprising the first identifier of the apparatus.

### Claim 40 (depends on 39)

The central network instance of claim 39, wherein said information further comprises at least one of:
a set of system parameters, and/or
the private key SKi, and/or
a public key PKi associated with the apparatus, and, wherein the set of system parameters comprises at least one of:
a first hash function, and/or
a second hash function, and/or
a third hash function, and/or
a generator q, and/or
a function e associated with bilinear pairing, and/or
a systems public key.

### Claim at position 23

-42. (canceled)

### Claim 43 (depends on 39)

The central network instance of claim 39, wherein the apparatus is further configured to perform:
receive a group session request message from each apparatus of the set of apparatuses;
obtain a session identifier associated with the communication session associated with the set of apparatuses;
determine an ordered structure of the apparatuses of the set of apparatuses; and
provide group information to each apparatus of the set of apparatuses.

### Claim 44

(canceled)

### Claim 45 (depends on 39)

The central network instance of claim 39, wherein the apparatus is further configured to perform:
for each apparatus of the set of apparatuses, receive a respective hash value based on the session key determined by the respective apparatus of the set of apparatuses; and
check, whether all hash values based on the session key are the same, and if this checking yields a positive result, activate the communication session,
wherein the set of apparatuses represent a group associated with the communication session; and
receive a message being indicative of a change of the membership in the group from an apparatus; wherein
if said change of the membership comprises at least one new apparatus joining or willing to join the group, for each of said at least one new apparatus:
determine a first identifier associated with the apparatus, wherein this apparatus is associated with a second identifier of the apparatus;
determine a private key associated with the apparatus; and
provide information to the apparatus comprising the first identifier of the apparatus.

### Claim at position 27

-59. (canceled)

### Claim 60

A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the following:
obtaining a first identifier associated with the apparatus, wherein the first identifier is different from a second identifier associated with the apparatus;
providing one or more messages to at least one further apparatus of a set of one or more apparatuses, wherein each of the one or more messages comprises key information of the apparatus and is associated with the first identifier associated with the apparatus; and
determining a session key of a communication session associated with the apparatus and at least one further apparatus, based on one or more messages received from at least one further apparatus of the set of one or more apparatuses, wherein each of the messages comprises key information of the respective further apparatus and is associated with a first identifier associated with the respective further apparatus.

### Claim 61

A non-transitory computer readable medium comprising program instructions for causing a central network instance to perform at least the following:
receiving a second identifier of an apparatus of a set of apparatuses, the apparatuses of the set of apparatuses being associated with a communication session;
determining a first identifier associated with the apparatus, wherein this apparatus is associated with the second identifier;
determining a private key associated with the apparatus; and
providing information to the apparatus comprising the first identifier of the apparatus.

### Claim 62

A system comprising a plurality of apparatuses, and at least one central network instance; wherein
the plurality of apparatuses are associated with a communication session;
wherein
an apparatus of the plurality of apparatuses comprises:
at least one processor, and
at least one memory including computer program code,
the at least one memory and the computer program code configured to, with the at least
one processor, cause the apparatus at least to perform:
obtain a first identifier associated with the apparatus, wherein the first identifier is different from a second identifier associated with the apparatus,
provide one or more messages to at least one further apparatus of a set of one or more apparatuses, wherein each of the one or more messages comprises key information of the apparatus and is associated with the first identifier associated with the apparatus, and
determine a session key of a communication session associated with the apparatus and at least one further apparatus, based on one or more messages received from at least one further apparatus of the set of one or more apparatuses, wherein each of the messages comprises key information of the respective further apparatus and is associated with a first identifier associated with the respective further apparatus; and wherein
the central network instance comprises:
at least one processor, and
at least one memory including computer program code,
the at least one memory and the computer program code configured to, with the at least
one processor, cause the central network instance at least to perform:
receive a second identifier of an apparatus of a set of apparatuses, the apparatuses of the set of apparatuses being associated with a communication session,
determine a first identifier associated with the apparatus, wherein this apparatus is associated with the second identifier,
determine a private key associated with the apparatus, and
provide information to the apparatus comprising the first identifier of the apparatus.