An Efficient Multi-Keyword Search Scheme over Encrypted Data in Multi-Cloud Environment

Recently multi-cloud has become the main model of cloud computing. With the rapid development of cloud computing technology, users are increasingly concerned about data security in the cloud. To ensure data security, users encrypt private data and upload it to cloud servers. Nevertheless, it is challenging to search ciphertexts with keywords from large amounts of encrypted data of multiple cloud servers. Moreover, existing attribute-based searchable encrypted schemes have several limitations, such as inflexible access control policy, only supporting single or conjunctive keyword search, and low search efficiency. Therefore, we propose an efficient Attribute-based Multi-keyword Search scheme (AMSE) over Encrypted data in multi-cloud environment. AMSE leverages the high-performance Ciphertext-Policy Attribute-Based Encryption (CP-ABE) algorithm to achieve multi-keyword ciphertext search and fine-grained access control. By introducing a retrieval server, AMSE can efficiently and accurately search ciphertexts in multi-cloud. The security analysis and performance evaluation demonstrate that AMSE is secure, highly efficient, and well-suited for multi-cloud.