Document clustering for efficient and secure information retrieval from cloud

Abstract

Summary Organizations prefer using cloud for storing their data due to availability of cost‐effective storage. The outsourced data include sensitive information, so data is encrypted as maintaining confidentiality and privacy of the documents is of paramount importance. Retrieving the desired information from the cloud requires efficient searching, which involves submission of search query to the cloud server by the end‐user. As the search terms may include sensitive information of an organization, it is desired that the search query should not reveal any confidential information. The existing works are not suitable for big‐data scenario due to high search time required for large document collections, thereby leading to increased cloud usage cost. Thus, an efficient approach to perform search on encrypted data using clustering is proposed in this paper. As the proposed technique clusters the documents based on the relationship between the keywords, the search method involves searching documents within the relevant cluster in contrast to searching the entire dataset. An efficient ranking method is incorporated to rank the documents according to the relevance to search query using Term Frequency‐Inverse Document Frequency (tf‐idf) value of the keywords in the documents, which leads to reduced communication overheads due to reduction in unnecessary documents being downloaded. Moreover, an efficient query randomization approach is proposed so that two or more queries involving the same search terms appear distinct. Experimental results using real datasets demonstrate that our proposed multi‐keyword ranked search scheme on encrypted cloud data significantly reduce the number of comparisons and search time in comparison to the existing techniques while maintaining recall of 100% and precision of 82%.

Searchable encryption: A survey on privacy‐preserving search schemes on encrypted outsourced data

“…14,[56][57][58]60,304 The comparison of the performances motivates the researchers to utilize the keyword field-free index structure so as to perform disjunctive searching over encrypted outsourced data. 14,[56][57][58]60,304 The comparison of the performances motivates the researchers to utilize the keyword field-free index structure so as to perform disjunctive searching over encrypted outsourced data.…”

“…Encryption (E) S o n g e t a l 37 vnE Pseudorandom function (f) Goh -The schemes proposed by Örencik and Savaş 12,14 and Handa et al [56][57][58]60,304 are fast in document retrieval, but they can support only conjunctive searching, ie, if all the search terms appear in a document, then it is labeled as a match; else, it is a mismatch. The comparison of the search efficiency of the typical SE schemes is presented in Table 16.…”

“…One of the alternatives to improve the trade-off is to utilize the scheme proposed by Wang et al 40 or its extensions 12,14,[56][57][58][59][60]139,304 to create an inverted index, which can then be utilized to perform disjunctive searching. As these schemes can support conjunctive searching by default, utilizing an inverted index can then support disjunctive searching.…”

Efficient privacy‐preserving scheme supporting disjunctive multi‐keyword search with ranking

“…To further reduce the search time, cluster-based and keyword binning-based search schemes were proposed. 20,24,26,38 The proposed schemes were efficient in searching only the documents, including all the search terms. On the other hand, support for disjunctive keyword searching was introduced by Cao et al 27 The proposed scheme was able to retrieve the documents containing a subset of the search terms but required large matrix multiplications to retrieve results, thereby leading to increased search time.…”

“…As the collection size increased, the search time also increased. To further reduce the search time, cluster‐based and keyword binning‐based search schemes were proposed . The proposed schemes were efficient in searching only the documents, including all the search terms.…”