Encrypted Document Digest for Privacy-Preserving Personal Search
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Solution Overview
Problem
Cloud storage systems face privacy concerns as documents and metadata are accessible in cleartext, making users vulnerable to data breaches if the service is compromised.
Innovation Solution
A method where a personal cleartext document is encrypted on a client device, generating an encrypted document digest and document, which is then used to build a personal search index on a server, allowing for opaque search queries and results, ensuring that only encrypted data is transmitted and stored, maintaining user privacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If documents and metadata are stored in cleartext on cloud storage systems, then search functionality is simplified and fast, but user privacy and security are compromised making users vulnerable to data breaches
Solution Approach 1:
The system performs preliminary encryption of documents and generation of encrypted digests before uploading to the cloud storage system. This advance preparation ensures that data is protected before it enters the potentially vulnerable cloud environment, eliminating the need to store cleartext while maintaining search capability through the trusted client device.
Solution Approach 2:
The trusted client device acts as an intermediary between the user and the cloud storage system. It generates encrypted document digests and handles search queries without exposing cleartext data to the cloud provider. This intermediary maintains both privacy protection and search functionality by performing operations locally while enabling cloud-based storage.
2Object-affected harmful factors
If encrypted data is transmitted and stored instead of cleartext, then user privacy is protected, but device complexity increases due to encryption and decryption operations
Solution Approach 1:
The system extracts the encryption and decryption operations from the cloud storage system and relocates them to the trusted client device. This separation allows the cloud provider to remain simple while the client device handles the complex cryptographic operations, distributing complexity to where it is most manageable and secure.
Solution Approach 2:
The system transforms data from cleartext to encrypted format using cryptographic parameters and algorithms. By changing the state of the data through encryption, the system protects privacy while the encrypted form can still be processed and stored efficiently, with decryption only occurring when needed on the trusted client device.
3Object-affected harmful factors
If encrypted document digests are used for searching, then cleartext data exposure is eliminated, but search query processing becomes more complex
Solution Approach 1:
The system creates encrypted copies of document digests that can be searched without exposing the original cleartext data. These encrypted digests serve as searchable representations that maintain the ability to retrieve relevant documents while preventing data exposure, as the cloud provider only handles encrypted values never revealing the underlying content.
Data Source
AI summary
Examples of the present disclosure describe systems and methods for enhancing the privacy of a personal search index. In some aspects, a personal cleartext document may be used to generate an encrypted document digest and an encrypted document on a first device. A second device may decrypt the document digest, build a personal search index based on the decrypted document digest, and store the encrypted document in a data store. The first device may subsequently receive a cleartext search query that is used to query the personal search index on the second device for encrypted documents.