Key Generation Device for Secure Keyword Search
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Solution Overview
Problem
Current public-key encryption with keyword search (PEKS) systems lack effective methods for securing the safety of the trapdoor, particularly in scenarios where the sender and receiver are different entities, and existing solutions are limited to exact match searches, failing to provide adequate security for more complex search queries like AND/OR searches.
Innovation Solution
A key generation device that separates the true public parameter and protection key within the public parameter, allowing for secure distribution and use in a secret search system, where the true public parameter is used for encryption, trapdoor generation, and secret search, while the protection key is used for encryption and trapdoor generation but not for the secret search, enhancing the security of the trapdoor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the public parameter is used for both encryption and secret search, then the system functionality is simplified, but the trapdoor security is compromised
Solution Approach 1:
The public parameter PK is segmented into two distinct components: true public parameter PP and protection key PK'. The true public parameter PP is used for secret search operations, while the protection key PK' is used for encryption and trapdoor generation. This segmentation ensures that the server conducting secret searches cannot generate valid trapdoors without the protection key, thereby securing the trapdoor against server-side attacks while maintaining system functionality.
2Adaptability or versatility
If the protection key is distributed to the server, then the secret search functionality is enhanced, but the trapdoor safety is reduced
Solution Approach 1:
The protection key PK' is extracted from the public parameter and distributed separately to the receiver. The server receives only the true public parameter PP, which is insufficient for generating trapdoors. This extraction ensures that even though the server has enhanced search functionality with the true public parameter, it cannot compromise trapdoor safety because the protection key required for trapdoor generation remains exclusively with the receiver.
3Reliability
If the public key is not released but treated similarly to the secret key, then the trapdoor safety is improved, but the applicable applications are limited
Solution Approach 1:
Different components of the public parameter are assigned different distribution qualities: the true public parameter PP is made publicly available to the server for search operations, while the protection key PK' is kept private and distributed only to the receiver for trapdoor generation. This local quality differentiation enables both broad application scope (server can perform searches) and high trapdoor safety (only receiver can generate trapdoors).
Data Source
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AI summary
A public parameter PK is key information used in a secret search system 1000 having: a transmission device 100 generating and sending an encryption tag which is an encrypted keyword; a server 200 receiving and storing the encryption tag and conducting a secret search in response to a request for the secret search; and a reception device 300 generating a trapdoor which corresponds to a digital signature of the keyword and as well data requesting the secret search, sending the trapdoor to the server 200, and receiving a search result. The public parameter PK includes a true public parameter PP and a protection key PK'. The transmission device 100 and the reception device 300 require both the public parameter PP and the protection key PK'; however, the server 200 does not require the protection key PK'. Accordingly, the key generation device 300 generates separately the true public parameter PP and the protection key PK' included in the public parameter PK.