Dynamic Searchable Encryption for Healthcare Data Privacy
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Solution Overview
Problem
Conventional searchable encryption technologies, such as static and dynamic SSE, fail to provide forward privacy and verifiability in healthcare settings, making it challenging for third-party healthcare service providers to query and utilize encrypted patient health information without infringing on patient privacy, especially in cloud-based systems.
Innovation Solution
A dynamic searchable symmetric encryption (DSSE) system with forward privacy and delayed verifiability is implemented, using an IoT gateway to aggregate and encrypt patient health information, a cloud network for secure storage, and a chaining scheme to link file identifiers, along with a bloom filter and aggregate message authentication code to ensure privacy and verifiability during searches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PHI is encrypted before outsourcing to cloud storage, then security and privacy compliance is improved, but query capability and data utilization are worsened
Solution Approach 1:
The system segments the encrypted database into multiple shards distributed across cloud servers. Each shard contains a portion of the encrypted data and its associated search index. This segmentation allows the cloud to perform searches on specific shards without requiring decryption of the entire database, thus maintaining both security and query capability.
Solution Approach 2:
The patent introduces a trusted third-party intermediary (such as a healthcare provider or authorized entity) that holds the decryption key. This intermediary acts as a mediator between the encrypted data on the cloud and the query requests. The intermediary can decrypt and process queries on behalf of users without the cloud server ever having access to the plaintext PHI, thus enabling both encryption-based security and functional query capability.
2Adaptability or versatility
If dynamic updates are allowed in searchable encryption system, then data freshness and adaptability are improved, but forward privacy is worsened
Solution Approach 1:
The system performs preliminary actions by pre-processing data during the upload phase. When data is uploaded to the cloud, the system immediately generates and stores search indices in encrypted form, and creates verification tokens that will be valid for future queries. This preliminary indexing and token generation enables the system to accept dynamic updates while maintaining forward privacy, as the verification infrastructure is already in place before any queries occur.
Solution Approach 2:
The patent implements dynamic searchable encryption where the system adapts to ongoing data updates. The search indices are dynamically updated alongside the data, and the verification mechanism uses timestamps and version counters that automatically adjust as new data is added. This dynamic approach allows the system to maintain both data freshness through continuous updates and forward privacy through cryptographic verification that prevents inference from access patterns.
3Reliability
If verification mechanism is added to ensure data integrity, then reliability and auditability are improved, but system complexity and computational overhead are worsened
Solution Approach 1:
The verification mechanism uses cryptographic copying rather than physical duplication. Instead of maintaining redundant copies of the actual PHI data for verification purposes, the system creates cryptographic hashes and digital signatures that serve as verification copies. These cryptographic copies are much smaller in size and can be efficiently stored and verified without the computational overhead of maintaining full data replicas, thus improving reliability while limiting the increase in system complexity.
Data Source
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AI summary
A DSSE architecture network enables multi-user such as data owners and data users to conduct privacy-preserving search on the encrypted PHIs stored in a cloud network and verify the correctness and completeness of retrieved search results simultaneously is provided. The data owners and data users may be patients, HSPs, or combination thereof. An IoT gateway aggregates periodically collected data into a single PHI file, extract keywords, build an encrypted index, and encrypt the PHI files before the encrypted index and PHI files are transmitted to a cloud network periodically for storage thus enable the DSSE architecture network to achieve a sub-linear search efficiency and forward privacy by maintaining an increasing counter for each keyword at the IoT gateway. Since the PHI files are always transmitted and added/stored into the cloud storage over the cloud network, file deletion, file modification is eliminated. The cloud network therefore does not need to learn whether the newly stored PHI files contain specific keywords. Any number of HSPs such as data users provides healthcare services for the patient by searching, querying, and/or retrieving user's encrypted PHIs incrementally stored on the cloud network in a privacy and verifiable manner. The patient delegated verifiability is derived from a combination of a Bloom filter and aggregate message authentication code.