Secure and Verifiable Multi-owner Ranked-Keyword Search in Cloud Computing

To preserve the privacy of cloud data, sensitive files are always encrypted by data owners, which let the keyword search be more difficult to the crucial applications. Thus, a secure and efficient keyword search protocol over encrypted files is required. Most of the prior keyword search works over encrypted cloud files focus on single-data-owner settings. However, there are a large number of data owners involved in real applications. To retrieve user required files, single-owner keyword search schemes need to be repeated several times to search over files encrypted by different unique private keys, which is a very costly way. To achieve high efficiency and privacy preserving in multi-data-owner scenario, we propose a Secure and Verifiable Multi-owner Ranked-keyword Search protocol, named SVMRS, in this paper. Specifically, to preserve privacy and to improve the keyword search precision, we combine a modified asymmetric scalar-product encryption function with the TFtimesIDF rule. Furthermore, to preserve the integrity of search results, we extend the SVMRS based on circular bidirection-linked list, which can make the query result verifiable. Detailed analysis and experiments show that the SVMRS can preserve the file privacy and integrity, and confirms the high efficacy and efficiency of SVMRS.