Achieving Verifiable Assured Deletion For Cloud Data

The rapid development of cloud computing technology not only has promoted the process of the information of human society greatly,but also has a profound influence on the whole internet industry.Cloud storage technology is widely used as an important service for cloud computing technology.More and more enterprises and personal choose to store or share data into the cloud environment.But when users need to delete data,the cloud storage server will dishonest operate and attempt to retain the user data,and there will cause the problems of privacy data leakage and data abuse.In addition,when the user deletes the data stored in the cloud,how to confirm whether the cloud service provider accurately executes the delete operation and whether the deleted data is unrecoverable and permanently invalid which is a challenge of cloud data security and affects the healthy development of cloud storage computing.According to the above problems,the main research contents are as follows:Firstly,in order to solve the problem that the leakage of privacy data,unauthorized access and lack of effective feedback mechanism in data assured deletion.This paper introduces a verifiable deletion method which combines DHIES,verifiable calculation and permutation function.The data owner uploads a random data to the cloud and use the permutation function to overwrite the key.The key management server obtains the validator through the hash operation of the random data and sends back the new key and validator to the data owner.The data owner should compare the new key with the validator to verify whether the key is assured deletion.The analysis proves that this scheme is effective to solve the problem of data assured deletion in cloud computing.Secondly,the ciphertext still exists in the cloud storage server,the untrusted third party will dishonest delete the data and attempts to retain the data which will cause privacy data leakage and data residue problems.This academic dissertation introduces a verifiable assured deletion method based on interactive overwriting which combines convergent encryption and random generating number method.In order to delete the ciphertext,the cloud use a random data generation method and a random data blocks to generate new data blocks to overwrite the original data blocks.The data owner sends authentication seed to cloud storage server,then the cloud storage server use the seed and overwrited data to generate a new validator and sent it to the owner.The data owner verifies whether the ciphertext is deleted by checking the correctness of the feedback information from the cloud storage server.At last,the feasibility of the scheme is verified by the simulation experiment,which proves the practicability of the scheme.