Wireless Group Key Update via Time-Based User Segmentation
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Solution Overview
Problem
The frequent key updates in wireless communication systems due to dynamic group membership changes incur high communication and security costs, necessitating an efficient group key reconfiguration method for multicast services.
Innovation Solution
A method and apparatus for sorting users departing a group into subgroups based on their entry and departure times, updating subgroup and group keys in a batch manner, and transmitting the updated keys to remaining users, thereby reducing key storage costs and balancing the key tree.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequent key updates are performed to maintain security when group members dynamically join and leave, then security is improved, but communication cost and security cost increase
Solution Approach 1:
The patent combines multiple key update operations into a single batch update. When multiple users depart from the group, instead of performing separate key updates for each user, the system merges these updates into one operation that updates all affected keys simultaneously, thereby reducing the total number of communication rounds and security operations required
Solution Approach 2:
The patent performs preliminary sorting of departing users by their departure times before executing key updates. By organizing users into groups based on when they leave the system, the patent prepares the update structure in advance, allowing for more efficient batch processing and reducing the computational overhead during the actual key update execution
2Reliability
If individual key updates are performed for each departing user, then security is maintained, but the number of keys to store and update increases
Solution Approach 1:
The patent merges the key update operations for multiple departing users into a single batch operation. By identifying all users who depart within a certain time window and updating their keys together, the system reduces the total number of keys that need to be stored and managed, as well as the number of separate update operations required
Solution Approach 2:
The patent segments the group of departing users into subgroups based on their departure times. This segmentation allows the system to process key updates in organized batches rather than as individual operations, making the key management process more efficient and reducing the overall key storage requirements
3Productivity
If batch key updates are performed to reduce communication cost, then communication efficiency is improved, but the sorting and organization of users becomes more complex
Solution Approach 1:
The patent performs preliminary sorting of users based on their departure times before executing batch key updates. By organizing users into groups according to when they will leave in advance, the system simplifies the batch update process and makes the sorting operation more manageable, reducing the complexity during the actual update execution
Data Source
AI summary
The present invention relates to a method and apparatus for updating a key for encrypting multicast data in a wireless communication system. The method of the present invention is characterized by comprising: an information receiving step of receiving information on a group entry time and a group exit time from users who have newly entered an arbitrary group including at least one subgroup; a grouping step of grouping the users using the information on the group entry time and the group exit time; and a key transmission step of either transmitting, to the newly-entered users, keys related to the group and the subgroups, or updating, for the remaining users of the subgroups, both the key related to the subgroup to which the user exiting the group belongs and the key of the group and then transmitting the updated keys to the users of the subgroups.