Selective SCG Key Synchronization in 5G Dual Connectivity
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Solution Overview
Problem
In wireless communication systems, particularly in dual connectivity scenarios, there is a challenge in synchronizing security keys between terminals and secondary nodes when repeated conditional secondary node changes occur.
Innovation Solution
The method involves sharing capabilities for selective SCG (Secondary Cell Group) between the terminal and the master node, allocating multiple SN counter values to each secondary node, and generating corresponding KSN keys. These keys are then used for encryption and integrity protection in user plane data exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple SN counter values are allocated to each secondary node for repeated conditional SN changes, then key synchronization reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the key management process by allocating multiple SN counter values (first SN counter value, second SN counter value, etc.) to each secondary node. Each counter value is associated with a specific key (first key, second key), creating segmented key pairs that can be independently managed. This segmentation allows the terminal to selectively use appropriate keys based on which SN counter value is received from the master node, thereby improving key synchronization reliability without requiring complete reconfiguration of the entire security system.
Solution Approach 2:
The patent implements preliminary action by pre-allocating multiple SN counter values and corresponding keys to secondary nodes before actual conditional SN changes occur. The terminal receives and stores multiple candidate SN counter values from the master node in advance, along with their associated keys. When a conditional SN change occurs, the terminal can immediately use the pre-prepared key corresponding to the received SN counter value, eliminating key synchronization delays and improving reliability without adding operational complexity.
2Reliability
If multiple keys are generated and managed for selective SCG, then security is improved, but ease of operation deteriorates
Solution Approach 1:
The master node serves as an intermediary that manages the complexity of multiple key operations. The terminal receives SN counter values from the master node, which then provides the corresponding key information. This intermediary role allows the terminal to operate with simplified logic (receive SN counter, use associated key) while the master node handles the complex key generation, management, and distribution. The intermediary approach maintains security through multiple keys while preserving ease of operation at the terminal.
Solution Approach 2:
The patent uses copying by creating multiple key copies (first key, second key, etc.) associated with different SN counter values. Instead of requiring the terminal to generate or manage complex key relationships, the system creates simplified copies of authentication material that can be independently used. Each key copy is tied to a specific SN counter value, allowing the terminal to operate with simple key selection based on received counter values, thereby maintaining ease of operation while ensuring security through multiple key instances.
Data Source
AI summary
The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method and apparatus of a master node (MN) are provided. The method of MN comprises: transmitting, to at least one target secondary node (SN), an SN addition request message including at least one SN counter value and KSN key corresponding to each target SN, wherein each target SN includes a first target SN and a second target SN; transmitting, to a user equipment (UE), a first radio resource control (RRC) reconfiguration message including the at least one SN counter value and the KSN key corresponding to each target SN; and transmitting, to the first target SN, an SN reconfiguration complete message including an SN counter value received from the UE.