Relay communication methods and apparatuses, communication device, and storage medium

A relay communication method, performed by a second user equipment (UE), and comprising:

• before a relay communication discovery between a first UE and the second UE:
• sending a security information request message to a second network node so that the security information request message is sent to a first network node by the second network node, wherein the security information request message is configured to request security information for protecting the relay communication discovery between the first UE and the second UE;
• and
• receiving a security information response message sent by the second network node, wherein the security information response message is sent by the first network node and comprises the security information;
• wherein the security information request message comprises:
• a key request message;
• the security information response message comprises:
• a key response message;
• and the security information comprises:
• a discovery intermediate key;
• wherein the key request message comprises:
• a relay service code (RSC) indicating a relay service;
• the key response message comprises the discovery intermediate key for the RSC;
• and/or
• the key request message further comprises second security indication information, configured to indicate security capability of the second UE, and/or
• the key response message comprises at least one of:
• an algorithm identification, wherein the algorithm identification comprises at least one of:
• a first algorithm identification, configured to indicate an algorithm for encrypting and decrypting a discovery message of a relay communication;
• or a second algorithm identification, configured to indicate an algorithm for performing integrity protection on the discovery message of the relay communication;
• time-related information, configured to determine whether the discovery message of the relay communication is subject to replay attacks.

A relay communication method, performed by a first network node, and comprising:

• before a relay communication discovery between a first user equipment (UE) and a second UE:
• receiving a security information request message, wherein the security information request message is configured to request security information for protecting the relay communication discovery between the first UE and the second UE;
• and
• sending a security information response message, wherein the security information response message comprises the security information;
• wherein the security information request message comprises:
• a key request message;
• the security information response message comprises:
• a key response message;
• and the security information comprises:
• a discovery intermediate key;
• wherein the key request message comprises:
• a relay service code (RSC) indicating a relay service,
• the key response message comprises the discovery intermediate key for the RSC,
• wherein the receiving the security information request message comprises:
• receiving the key request message sent by the first UE;
• the sending the security information response message comprises:
• sending the key response message to the first UE in response to determining that the first UE is authorized to provide the relay service, and/or
• the receiving the security request information message comprises:
• receiving the key request message sent by a second network node, wherein the key request message is sent after the second network node determines that the second UE is authorized to discover the relay service;
• the sending the security information response message comprises:
• sending the key response message to the second network node,
• wherein the sending the key response message to the second network node comprises:
• sending the key response message to the second network node in response to determining that the first UE is authorized to provide the relay service to the second UE, and/or
• the key request message further comprises at least one of:
• type indication information, configured to indicate a discovery message type of a relay communication;
• first security indication information, configured to indicate security capability of the first UE;
• or
• second security indication information, configured to indicate security capability of the second UE, and/or
• the key response message comprises at least one of:
• an algorithm identification, wherein the algorithm identification comprises at least one of:
• a first algorithm identification, configured to indicate an algorithm for encrypting and decrypting a discovery message of a relay communication;
• or a second algorithm identification, configured to indicate an algorithm for performing integrity protection on the discovery message of the relay communication;
• or
• time-related information, configured to determine whether the discovery message of the relay communication is subject to replay attacks.