Research Of Users' Data Privacy-preserving Technology In Cloud Computing

Cloud computing is a new type of data calculation and sharing model,it is developed by parallel computing,grid computing,distributed computing and other traditional models.Its characteristics are computationally efficient,cost-effective,and easy to use.Because of these advantages,more and more users will upload own data from local host to the cloud,in order to enjoy fast sharing of resources and efficient computing.But,cloud computing not only brings users efficient and convenient services,but also the data security problem.How to protect data security has become a bottleneck in the development of cloud computing.Privacy protecting technology is one of the core technologies which ensure data security.Through these methods just like encrypting data,assured deleting overdue the cloud data and searching data in encryption the security of data can be protected.Traditional privacy protecting scheme has all kinds of problems.For example: conditional proxy re-encryption scheme exist a problem which protecting condition imperfectly;cipher-text searching scheme exist a problem which has lower accuracy and tolerance rate;overdue data assured deleting scheme exist a problem that lack trust value evaluation for nodes of storing keys.Aiming at the problems of traditional privacy protecting technology,this paper has carried on the thorough research from three aspects which are conditional proxy re-encryption scheme,ciphertext searching scheme and overdue data assured deleting scheme and put forward corresponding innovative scheme.The main contents are summarized as follows.Firstly,the traditional conditional proxy re-encryption scheme in cloud computing exists this problem.It is lacking of protection,thus it is easily obtained by attacker and the identity of data owner would be guessed.Then the attacker guesses the key.In the end the privacy data would be leaked.For this problem,this paper use DNA coding to encrypt the condition,hiding condition information.Attacker is unable to obtain data owner identity information by condition.This paper using IND-CPA to prove its security under DBDH complexity issue.Secondly,the traditional cipher-text searching scheme in cloud environment exist a problem which has lower accuracy and tolerance rate.For this problem,this paper proposes a double-trap searching scheme.First of all,constructing a double-index structure,the scheme can support parallel operation of multi-keyword searching and fuzzy searching.In the next place introducing the Huffman coding tree and DFSC to build the index structure.It improves tolerance rate and reduces the index storage space.At last using the TF-IDF rule to hide the keyword frequency.This paper puts forward the scheme of indexing,trapdoor and searching process safety analysis,it is proved that the scheme is secure,and the experiment results show that the proposed scheme can effectively improve the tolerance rate and reduce the storage space.Thirdly,the traditional overdue data assured deleting scheme in cloud environment exist a problem which is lacking of trust value evaluation for DHT nodes.If the key component is stored on the untrusted or dishonest DHT nodes,it is easy to cause the key component to be stolen,and causes the key to be maliciously recovered.Then leading to the privacy data leakage.This paper proposes a overdue data assured deleting scheme based on trust value evaluation,through the assessment of the value of DHT node for storing the key components of the fine-grained trust,the user can select a key component storage node trust value is higher.The experimental results show that the scheme can effectively improve the success rate of obtaining the key component.