Multi-server searchable data crypt: searchable data encryption scheme for secure distributed cloud storage

摘要

This paper introduces a multi-server searchable symmetric encryption (SSE) scheme called the Multi-Server Searchable Data Crypt "MS-SDC" that works on achieving a trade-off between efficiency/functionality and security. The proposed scheme has the merits of dividing the uploaded file in an encrypted form into blocks and distributing them across several storage providers, which is more acceptable than uploading the whole file directly to a single server where each server only holds a subset of file/block, to ensure more security for the file. Besides that, it extracts keywords for each uploaded file to be used later by the search engine giving the user the ability to browse across his own files. This means that the user has the ability to query/search for his encrypted files on the server-side without decrypting them. Furthermore, there are various features proposed different from those presented by previous works as the scheme is developed as a multithreaded-application to speed up the uploading time, and a unique master key is generated randomly for each uploaded file unlike the previous techniques where a single master key is created randomly for all the uploaded documents leading to easily hacking the system with master key leakage. Finally, the MS-SDC system is distinctive in its smooth usage and its robustness where it can run on any browser and can be applied to any file type. The experimental results demonstrate the effectiveness of our proposed system in comparison to previous works in terms of uploading and searching time, in addition to providing many new features, applying many layers of security, and keeping high-speed performance in an efficient manner. The proposed system has reduced the file upload time up to 64% of the current research upload time via multithreading implementation of the block distribution function.