Decipherable Searchable Encryption Key Segmentation
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Solution Overview
Problem
Current encryption methods allow for keyword search but not decryption, and vice versa, limiting the ability to access specific encrypted information while maintaining confidentiality, particularly in scenarios where third parties need to inspect encrypted data without decrypting all content.
Innovation Solution
A method that generates public and decryption keys, along with a derivation key, enabling both decryption of messages and keyword search by using key encapsulation and identity-based key encapsulation algorithms to create searchable traps without compromising confidentiality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional searchable encryption methods are used, then keyword search capability is improved, but decryption capability deteriorates (gateway cannot decrypt ciphertext)
Solution Approach 1:
The patent segments the cryptographic key into two distinct parts: a decryption key for decrypting ciphertext and a derivation key for generating search traps. This segmentation allows the system to perform both decryption and keyword search operations independently without compromising either capability. The decryption key enables full decryption while the derivation key enables searchable encryption through trap generation.
2Adaptability or versatility
If conventional decipherable encryption is used, then decryption capability is improved, but selective access capability deteriorates (must decrypt all information)
Solution Approach 1:
The patent applies local quality by making different parts of the key serve different functions: the decryption key provides full access for authorized decryption while the derivation key provides selective access for keyword search. This allows third parties to search for specific keywords without accessing the entire encrypted dataset, maintaining confidentiality of non-matching information while enabling targeted access.
3Device complexity
If a single key is used for both decryption and search operations, then system complexity is reduced, but security deteriorates (compromise of one key affects both functions)
Solution Approach 1:
The patent segments the cryptographic key into a decryption key and a derivation key, allowing each key to be optimized for its specific function. This segmentation enhances security because compromising one key does not necessarily compromise the other function. The decryption key remains secure for decryption operations while the derivation key enables safe keyword search operations.
Data Source
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AI summary
The invention concerns a method for encrypting/decrypting a message (m) including the following steps: generating keys comprising sub-steps which consist in: generating a public key (pk); generating a decryption key (dk); generating a derivation key (tk); for a first entity, encrypting said message (m) using said public key (pk) and a cipher (c); for a second entity, decrypting the cipher (c) to find said message (m); generating a trapdoor associated with said message (m), said trapdoor corresponding to a derivative of said derivation key specific to said message (m); for a test cipher (c'), testing, using said trapdoor associated with said message (m), if the test cipher (c') is an encryption (c) of said message (m) using said public key (pk).