Searchable Encryption System Role-Based Access Control
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Solution Overview
Problem
Existing searchable encryption systems lack efficient and secure mechanisms for revoking search privileges, particularly in group settings, leading to issues with data access control and privacy management when user roles or privileges change, such as during transfers or resignations.
Innovation Solution
A searchable encryption system that utilizes predicate encryption for inner products, generating a pair of secret and search auxiliary keys, requiring both for decryption, allowing flexible control of data access based on user roles and enabling secure revocation of search privileges by deleting the search auxiliary key.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If searchable encryption is implemented using public key encryption or common key encryption, then keyword search on encrypted data is enabled, but flexible control of data retrieval based on user roles or privileges cannot be achieved
Solution Approach 1:
The patent segments the access control mechanism by introducing attribute vectors and predicate vectors that can be independently configured. Data is encrypted with attribute vectors, and search keys are generated with predicate vectors, allowing fine-grained control over which users can search for which data based on their roles and privileges.
Solution Approach 2:
The patent changes the parameters of the encryption system by moving from traditional public key or common key encryption to predicate encryption with inner products. This introduces new parameters (attribute vectors, predicate vectors, inner product thresholds) that enable flexible role-based access control while maintaining search functionality.
2Measurement precision
If all encrypted data is downloaded and decrypted for keyword search, then complete search accuracy is achieved, but communication time and processing time are extremely long
Solution Approach 1:
The patent performs preliminary actions by pre-computing and storing attribute vectors in the encrypted data and predicate vectors in the search keys. This allows the search server to perform inner product computations directly on encrypted data without downloading or decrypting it, achieving both search accuracy and time efficiency.
Solution Approach 2:
The patent introduces an intermediary mechanism (the inner product computation between attribute vectors and predicate vectors) that enables search without full decryption. The inner product serves as a mediator that reveals only whether a match exists, not the actual data content, thus maintaining security while enabling efficient search.
3Adaptability or versatility
If searchable encryption allows any user to encrypt and retrieve data, then ease of data sharing is achieved, but secure control of data access based on user roles is lost
Solution Approach 1:
The patent applies local quality by assigning different attribute vectors to different data items based on their sensitivity and access requirements. Each data item can have its own access control policy encoded in its attribute vector, allowing fine-grained control over which users can search for which specific data based on their roles and privileges.
4Adaptability or versatility
If predicate encryption with attribute vectors and predicate vectors is used, then flexible role-based access control is achieved, but system complexity increases
Solution Approach 1:
The patent achieves universality by designing a unified predicate encryption framework that handles both data encryption and access control through the same mathematical mechanism (inner products of vectors). This multi-functional approach allows the system to simultaneously provide searchable encryption, role-based access control, and efficient search without requiring separate mechanisms for each function.
Data Source
AI summary
A search execution device receives a trapdoor generated based on a user secret key in which a search auxiliary key and an attribute of a user are set and a search keyword, together with a key identifier (ID) that identifies the search auxiliary key. The search execution device decrypts an encrypted tag in which an attribute of a user who is allowed retrieval and a search word are set, using the received trapdoor and the search auxiliary key indicated by the received key ID, so as to identify a tag that is retrievable for the attribute set in the user secret key and contains a search word corresponding to the search keyword.