With the rapid development of cloud storage technology,it is favored by many users because of its flexible management,low price,and convenient data access.However,in recent years,incidents of cloud data leakage continue to occur in some large cloud service providers(CSPs),making users begin to pay attention to cloud data security issues.To ensure the security of data in the cloud,data is usually encrypted and then stored.However,this method has certain limitations in the storage security and retrieval efficiency of encrypted data.Therefore,how to improve the security of cloud data storage and how to improve the retrieval efficiency of encrypted cloud data are the key issues in the current cloud security research.In view of this,this article will conduct in-depth research on the two aspects of efficient search and authorized search of ciphertext.The research content of the paper mainly includes the following two aspects:First of all,aiming at the problem of low query and storage efficiency in traditional cloud storage algorithms in cloud storage environment,this paper proposes a blind storage algorithm based on counting Bloom filter(CBF-BS).CBF-BS stores data on the server by splitting,encrypting,and obfuscating the data.Compared with the traditional BS algorithm,the proposed algorithm confuses the actual document blocks,not only ensures the security of the cloud data,but also avoids the traditional BS algorithm to use invalid data blocks as an obfuscated block,resulting in wasted storage space.The problem.In addition,the CBF-BS algorithm uses CBF to index the stored data.The query complexity is only related to the number of hash functions.The traditional BS algorithm uses a pseudo-random algorithm to index the stored data.Its query complexity is related to the number of documents.On the premise of ensuring the maximum misjudgment rate allowed by the system,the number of hash functions used by CBF is far less than the number of stored documents.Therefore,CBF-BS can effectively improve the query efficiency.Finally,theoretical analysis and simulation experiments show that the storage and query efficiency of CBF-BS has improved significantly.Secondly,after deeply researching the current mainstream authorizing search scheme,it is found that most of the programs rely on the authorization center to formulate the access control strategy and do not support the sorting of search results.In view of this,this paper proposes an Authorized Ciphertext Retrieval Scheme that supports the ordering of results(ARSS).This scheme replaces Authorization Centers with multiple Authorities to perform rights authentication on the basis of Blind Storage Algorithms,not only avoiding the possibility that a single Authorization Center may suffer.Attacks cause the risk of important data leakage,and multiple authorized organizations jointly perform privilege authentication,which can effectively improve the efficiency of authentication.In addition,the scheme introduces the concept of document similarity weights and uses the weights as the ranking of search results.In this way,users can obtain more accurate search results to enhance the user's search experience.Finally,theoretical analysis and simulation results verify the effectiveness of the scheme. |