Adaptive Decryption Key Switching via CRC Verification
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Solution Overview
Problem
Existing broadcast-type communication systems require strict synchronization and key distribution methods to ensure authorized users can decrypt data using updated decryption keys, while preventing unauthorized users from accessing the data, which can be challenging in maintaining network synchronization and key distribution.
Innovation Solution
A method and device for terminal equipment that stores multiple decryption keys, allowing adaptive key switching by using a trial and error decryption process with Cyclic Redundancy Code Check (CRC) to select a valid key for decrypting service data, without requiring strict synchronization or specific key distribution methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strict synchronization mechanism is implemented to ensure key switching, then decryption reliability is improved, but device complexity and network overhead increase
Solution Approach 1:
The terminal performs self-service key switching by autonomously testing stored decryption keys against received data frames using CRC verification. The system automatically identifies the valid key without external coordination, eliminating the need for complex network synchronization mechanisms while maintaining decryption reliability.
Solution Approach 2:
The system uses CRC check results as feedback to determine whether a tested decryption key is valid. Based on this feedback mechanism, the terminal can autonomously identify the correct key from multiple stored candidates, replacing complex synchronization protocols with simple error-detection-based key validation.
2Adaptability or versatility
If multiple decryption keys are stored at terminal for adaptive switching, then adaptability is improved, but device complexity increases
Solution Approach 1:
The terminal pre-stores multiple decryption keys before key switching is needed. When a key update occurs, the terminal can immediately test these pre-stored keys against received data frames, enabling rapid adaptive key switching without complex real-time key management procedures.
Solution Approach 2:
The system stores more decryption keys than strictly necessary (excessive action) to ensure adaptability during key transitions. By maintaining a pool of candidate keys and using simple CRC-based testing, the system achieves high adaptability with minimal processing complexity.
3Ease of operation
If trial and error decryption method with CRC check is used, then ease of operation is improved, but processing time increases
Solution Approach 1:
The key validation process is segmented into independent trial operations, where each stored decryption key is tested separately against the data frame using CRC check. This segmentation allows the system to quickly identify the valid key through systematic testing without requiring complex coordinated operations, improving ease of operation while keeping processing time acceptable.
Data Source
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AI summary
Embodiments of the present invention disclose a method of key switching for decrypting service data at a terminal, which includes: storing at least two decryption keys at a terminal side for decrypting service data encrypted by network side using a corresponding encryption key, wherein one of the at least two decryption keys is a current decryption key; receiving current service data and using the stored keys to decrypt the service data; and selecting from the stored decryption keys a key with which the current service data can be successfully decrypted and taking the selected key as the current decryption key. The embodiments of the present invention further disclose a data decryption device and a terminal equipment with the corresponding decryption function. With the invention, key switching can be performed adaptively, without special requirements on key distribution mode and synchronization, or additional overhead for supporting a strict data frame synchronization mechanism.