CSEIT1838111 | Received : 05 Jan 2019 | Accepted : 18 Jan 2019 | January-February -2019 [ 5 (1) : 74-78 ] International Journal of Scientific Research in Computer Science, Engineering and Information Technology © 2019 IJSRCSEIT | Volume 5 | Issue 1 | ISSN : 2456-3307 DOI : https://doi.org/10.32628/CSEIT1838111 74 Enhanced Security for Dynamic Multi Keyword Ranked Search Using Greedy Best First Search Bibin Baby 1 , Sharmila Banu 2 1 Assistant Professor, Department of Computer Science, Nilgiri College of Arts and Science, Thaloor, The Nilgris, Tamil Nadu, India 2 Assistant Professor, Department of Computer Science, Providence College for Women, Coonor, The Nilgiris, Tamil Nadu, India ABSTRACT Today, due to the enormous growth of data technology in cloud computing, the data owners are stimulated to outsource their data in data management to reduce cost and for the convenient. Data confidentiality, in general, can be obtained by encrypting the data before it is outsourced. The client stores the encrypted data to the cloud using Searchable encryption schemes and applies keyword search techniques over cipher text domain. But the main problem in outsourcing is the lack of security and privacy for the sensitive data. So, to overcome this, for privacy requirement, the sensitive data can be encrypted before it is outsourced. Various methods were proposed to preserve the privacy and to provide security to the cloud data which are encrypted. Here in this paper, we proposed a tree-based search method over the encrypted datain the cloud that supports dynamic operation and multi-keyword ranked search. Clearly, the commonly used “inverse document frequency (IDF) term frequency (TF)” model and the vector space method are joined in the query generation and index creation to give multi-keyword ranked search. To get high search efficiency, a tree-type index structure, “Greedy Best- first Search” algorithm is proposed based on the tree- index. Keywords : Cloud Computing, Security, Multi Keyword Search, Greedy Best First Search, Inverse Document Frequency, Term Frequency I. INTRODUCTION Nowadays, cloud computing has been taken into consideration as a new edition of IT infrastructure, that may put together large beneficial useful resource of computing, storage and programs, and allow users to revel in ubiquitous, convenient and on-demand network get admission to a shared pool of configurable computing sources with splendid overall performance and minimal monetary overhead .Attracted by way of those appealing features, each individuals and firms are stimulated to outsource their facts to the cloud, rather of buying software program and hardware to manipulate the facts themselves. No matter the various blessings of cloud services, outsourcing touchy information (which includes e-mails, non-public health statistics, enterprise business enterprise finance records, authority’s files, and plenty of others) to far flung servers brings privacy worries. The Cloud Carrier Vendors (CSVS) that preserve the facts for users may also additionally get admission to users’ sensitive information without authorization. A fashionable technique to shield the information confidentiality is to encrypt the statistics earlier than outsourcing but, this will motive a big rate in phrases of records usability. For an example, the present techniques on keyword-based totally information retrieval, which