Secure Searchable Based Asymmetric Encryption in Cloud Computing

Cloud computing offers a wide range of services such as user demand network, operating systems, hardware, software and resources. These encouraging facilities and hassle free management of computing resources have attracted many users to outsource their data to untrusted servers. Cloud server may leak documents to unauthorized parties. Therefore, all documents need to be transmitted in ciphertext mode to keep user data confidential against an untrusted Cloud Service Provider (CSP). However, encrypting documents prevents user to search the outsourced documents directly. Regular encryption algorithms such as AES, RC4 and DES mechanisms have searching limitation; in which the whole ciphertext needs to be retrieved and then decrypt before search procedure can be performed. Recently, many advanced encryption techniques have been proposed to enable search capabilities for users. Generally, the keyword based search approach is used. This approach allows users to retrieve only those documents contain special keywords. However, searchable encryption algorithms suffer from security problems. This paper first explains Public key Encryption with Keyword Search (PEKS) algorithm and then proposes an improved secure searchable encryption algorithm based on Indistinguishability under Adaptive Chosen Ciphertext Attack (IND-CCA2). The proposed searchable encryption is mathematically proven secure and it has the ability to perform a search within encrypted data.