A Lightweight Privacy Preserving Keyword Search Over Encrypted Data in Cloud Computing

With the emerging development of cloud computing services, data owners outsource their documents to Cloud Service Providers (CSP) which could lead to threats related to security and privacy. Hence, protecting the privacy of user data and providing queries privacy becomes one of the main concerns of the data owner. One of the solutions for providing privacy and confidentiality of the outsourced data is encrypting it before sending it to the cloud. Although this solution satisfies data confidentiality and prevents the CSP from reading or modifying the data without the data owner's permission, it prevents the data owner to search the outsourced documents directly. Symmetric encryption algorithms e.g. AES have a searching limitation, in which the whole encrypted document needs to be retrieved from the CSP and then decrypt before performing the search procedure. To overcome this limitation, a lot of keyword-based search approaches have been done. These approaches allow users to retrieve just those documents contain special keywords. However, most of these approaches suffer from privacy and security problems and are based on high overhead asymmetric encryption algorithms. This paper proposes a privacy-preserving keyword search scheme for searching over encrypted data. To avoids the high computational cost of asymmetric encryption, the proposed scheme employs symmetric encryption and Bloom filter. Experimental results demonstrate that the proposed searchable encryption algorithm is secure and lightweight, and it has the ability to perform a keyword search over encrypted data without decrypting them.