The document discusses a privacy-preserving multi-keyword ranked search (MRSE) system for encrypted cloud data, addressing the limitations of existing searchable encryption methods that typically focus on single or Boolean keyword searches. It establishes strict privacy requirements and introduces a new relevance measure called 'coordinate matching' to evaluate search results. The proposed system architecture includes modules for user registration, file upload with encryption, ranked searching, and secure downloads, demonstrating low computational and communication overhead.

1. Privacy-Preserving Multi-keyword
Ranked Search
over Encrypted Cloud Data
P R I V A C Y - P R E S E R V I N G M U L T I - K E Y W O R D R A N K E D S E A R C H
O V E R E N C R Y P T E D C L O U D D A T A
N I N G C A O † , C O N G W A N G ‡ , M I N G L I † , K U I R E N ‡ , A N D W E N J I N G L O U †
† D E P A R T M E N T O F E C E , W O R C E S T E R P O L Y T E C H N I C I N S T I T U T E , E M A I L : { N C A O , M I N G L I , W J L O U }@ E C E . W P I . E D U ,
‡ D E P A R T M E N T O F E C E , I L L I N O I S I N S T I T U T E O F T E C H N O L O G Y , E M A I L : { C O N G , K R E N }@ E C E . I I T . E D U

2. Abstract
With the advent of cloud computing, data owners are motivated to outsource their complex data
management systems from local sites to the commercial public cloud for great flexibility and
economic savings. But for protecting data privacy, sensitive data has to be encrypted before
outsourcing, which obsoletes traditional data utilization based on plaintext keyword search. Thus,
enabling an encrypted cloud data search service is of paramount importance. Considering the large
number of data users and documents in the cloud, it is necessary to allow multiple keywords in the
search request and return documents in the order of their relevance to these keywords. Related
works on searchable encryption focus on single keyword search or Boolean keyword search, and
rarely sort the search results. In this paper, for the first time, we define and solve the challenging
problem of privacy preserving multi-keyword ranked search over encrypted cloud data (MRSE).We
establish a set of strict privacy requirements for such a secure cloud data utilization system. Among
various multi keyword semantics, we choose the efficient similarity measure of “coordinate
matching”, i.e., as many matches as possible, to capture the relevance of data documents to the
search query. We further use “inner product similarity” to quantitatively evaluate such similarity
measure. We first propose a basic idea for the MRSE based on secure inner product computation, and
then give two significantly improved MRSE schemes to achieve various stringent privacy requirements
in two different threat models. Thorough analysis investigating privacy and efficiency guarantees of
proposed schemes is given. Experiments on the real-world dataset further show proposed schemes
indeed introduce low overhead on computation and communication.

3. Existing System
The large number of data users and documents in cloud, it is crucial for the search service to
allow multi-keyword query and provide result similarity ranking to meet the effective data
retrieval need. The searchable encryption focuses on single keyword search or Boolean keyword
search, and rarely differentiates the search results.

4. Disadvantages of Existing System
Single-keyword search without ranking
Boolean- keyword search without ranking
Single-keyword search with ranking

5. Proposed System
We define and solve the challenging problem of privacy-preserving multi-keyword ranked search
over encrypted cloud data (MRSE), and establish a set of strict privacy requirements for such a
secure cloud data utilization system to become a reality. Among various multi-keyword
semantics, we choose the efficient principle of “coordinate matching”.

6. Advantages of Proposed System
Multi-keyword ranked search over encrypted cloud data (MRSE)

7. Architecture

8. Modules
Data User Module
Data Owner Module
File Upload Module
Encryption
Rank Search Module
File Download Module
Decryption
View Uploaded and Downloaded File

9. Modules Description
Data User Module: This module include the user registration login details.
Data Owner Module: This module helps the owner to register them details and also include
login details.
File Upload Module: This module help the owner to upload his file with encryption using RSA
algorithm. This ensure the files to be protected from unauthorized user.

10. Rank Search Module: This module ensure the user to search the file that are searched frequently
using rank search.
File Download Module: This module allows the user to download the file using his secret key to
decrypt the downloaded data.
View Uploaded and Downloaded File: This module allows the Owner to view the uploaded files
and downloaded files

11. Minimum Hardware Configuration of the Proposed System
Processor : Intel/AMD
Hard Disk : 40 GB
Monitor : 14’ Colour Monitor
Mouse : Optical Mouse
RAM : 512 MB

12. Software Configuration of the Proposed System
Operating system : Windows 7 and above
Coding Language : ASP.Net with C#
Data Base : SQL Server 2008

13. References
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cloud definition,” ACM SIGCOMM Comput. Commun. Rev., vol. 39, no. 1, pp. 50–55, 2009.
S. Kamara and K. Lauter, “Cryptographic cloud storage,” in RLCPS, January 2010, LNCS. Springer,
Heidelberg.
A. Singhal, “Modern information retrieval: A brief overview,” IEEE Data Engineering Bulletin,
vol. 24, no. 4, pp. 35–43, 2001.
I. H. Witten, A. Moffat, and T. C. Bell, “Managing gigabytes: Compressing and indexing
documents and images,” Morgan Kaufmann Publishing, San Francisco, May 1999.
D. Song, D. Wagner, and A. Perrig, “Practical techniques for searches on encrypted data,” in
Proc. of S&P, 2000.