Dual-Connectivity Security-Key Derivation During Cell Reconfiguration
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Solution Overview
Problem
In mobile communication systems with dual connectivity, the continuous change of secondary cells without resetting leads to the same counter value being used for deriving security keys, potentially compromising communication protection between the communication apparatus and the secondary node.
Innovation Solution
A communication apparatus and base station system that utilizes a plurality of conditional reconfigurations to update the counter value for deriving a security key, ensuring different keys are used for each cell change, thereby maintaining appropriate communication protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the same counter value is used for deriving security keys during continuous cell changes, then the communication apparatus can maintain continuous connectivity without resetting, but the security protection is compromised due to repeated use of identical keys
Solution Approach 1:
The patent applies dynamics by making the counter value changeable rather than fixed. During conditional reconfiguration when a communication apparatus changes from a source secondary cell to a target secondary cell, the counter value is updated to reflect the new cell identity. This dynamic update ensures that each cell change results in a different security key, maintaining both continuous connectivity and security protection.
2Reliability
If the counter value is updated during conditional reconfiguration, then distinct security keys are generated for each cell change, but the complexity of key management increases
Solution Approach 1:
The patent applies self-service by enabling the communication apparatus to automatically update the counter value and derive new security keys without external intervention. The apparatus monitors cell changes and autonomously manages the counter value updates during conditional reconfiguration, eliminating the need for complex manual key management while maintaining distinct security keys for each cell.
3Adaptability or versatility
If conditional reconfiguration is used to enable continuous cell changes, then the communication apparatus can adapt to mobility, but the same security key may be reused across different cells
Solution Approach 1:
The patent applies local quality by associating unique counter values with specific cells. When a communication apparatus is configured with multiple conditional reconfigurations for different candidate secondary cells, each cell is assigned a distinct counter value. This ensures that even though the apparatus can adapt to mobility by changing cells, each cell maintains its own unique security key derived from its specific counter value, preventing key reuse across different cells.
Data Source
AI summary
A communication apparatus according to an embodiment is a communication apparatus that performs communication with a master cell group associated with a master node (MN) and a secondary cell group associated with a secondary node (SN). The communication apparatus comprises a receiver configured to receive a radio resource control (RRC) reconfiguration message from the master node, the RRC reconfiguration message including configuration information used to configure a plurality of conditional reconfigurations for configuring a plurality of candidate cells and information of a counter value used to derive a security key of the secondary node, a controller configured to select a cell fulfilling an execution condition from among the plurality of candidate cells, and derive the security key of the secondary node associated with the selected cell by using the counter value, and a transmitter configured to transmit the counter value used to derive the security key to the master node.