Research On Enterprise Cloud Storage Ciphertext Retrieval Based On Full Homomorphic Encryption

With the development of computer network,cloud storage has become one of the mainstream ways for people to store information.However,following the disclosure of some important information,information security has become one of the key issues in the development of cloud computing technology.Data stored in the cloud shall be encrypted to protect the integrity and security of sensitive data,however,it also results in the inability to directly manipulate the plaintext of the cloud data.This paper studies the ciphertext retrieval of enterprise cloud storage based on the full homomorphic encryption algorithm in order to ensure the security of data and improve the retrieval efficiency and accuracy when retrieving complex keywords in the cloud storage.This paper studies and designs the security encryption,decryption,retrieval algorithm and performance optimization scheme required by applying the full homomorphic encryption technology to the field of cloud storage enterprise file management,and implements a prototype system.The main work of this paper includes the following aspects:1.The characteristics of traditional encryption and holomorphic encryption are compared and analyzed.The principle,algorithm steps and homomorphism of traditional encryption and full homomorphism are compared and analyzed.It is believed that the homomorphism of the holomorphic encryption technology makes its advantages in the cloud computing environment stronger than the traditional encryption technology.2.A data encryption,decryption and retrieval algorithm based on full homomorphic encryption is proposed.Aiming at the low efficiency of DGHV scheme,the core formula of its encryption algorithm is improved,which directly expands the plaintext domain and speeds up the efficiency of operation.Aiming at the problem of single bit computation every time,an efficient multi-bit ciphertext retrieval algorithm is proposed,which improves the retrieval efficiency,saves space and system overhead.The improved algorithm is proved to be correct and safe in theory,and the experimental data show that the improved algorithm has better performance.3.A ciphertext retrieval algorithm based on full homomorphic encryption for enterprise cloud storage data is proposed.The C/S mode is adopted to design a prototype system,which realizes the cloud file management functions of cloud storage file upload,download,encryption,decryption,information retrieval and other security based on full homomorphic encryption.