A cloud storage encryption and deduplication method and system thereof

Abstract

The invention discloses a cloud storage encryption and dereplication method and a cloud storage encryption and dereplication system. The method comprises the following steps of: dividing a data file into a plurality of blocks, firstly transmitting an identification of each data block to a cloud storage system to perform the repetition detection, if the data file is not repeated, encrypting each data block by virtue of a convergence key, respectively encrypting each convergence key, storing a convergence key ciphertext of a first data block by virtue of a client, and storing convergence key ciphertexts of rest data blocks and all data block ciphertexts; and if the data file is repeated, generating a convergence key of the first data block, encrypting the convergence key by utilizing a root node of a hash tree transmitted by the cloud storage system, and storing the generated convergence key ciphertext of the first data block. By adopting the method and the system, the security of the data file can be improved when the convergence encryption and dereplication are adopted, a dictionary can be prevented from being cracked when in attack as far as possible, and the storage space of the client can be saved.

Description

technical field [0001] The invention relates to the technical field of cloud storage, in particular to a cloud storage encryption and deduplication method and system thereof. Background technique [0002] Deduplication technology is an important technology in the cloud storage system. By avoiding storing the same data files multiple times in the cloud storage system, it can save the hard disk space of the cloud storage system and the user's network bandwidth, thereby reducing the cost of the cloud storage system. . However, because data files often need to be encrypted when they are stored, if the user encrypts them first, and then the cloud storage system deduplicates them, different users often get different ciphertexts when encrypting the same data file, and the cloud storage system is very It is difficult to judge whether these different ciphertexts come from the same data file, which makes it impossible to de-duplicate encrypted data files. [0003] Currently, converg...

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Problems solved by technology

[0004] However, when using convergent encryption, since each data file uses the same encryption method, the encryption key of the data file is the same, and the encrypted data ciphertext is fixed, the attacker can use the dictionary to guess the content of the convergent key to decrypt The ciphertext of the data file, that is, the ciphertext of the data file is vulnerable to dictionary attacks and has poor security

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