Cloud data deterministic deletion system and method based on high inseparability of ciphertext

Abstract

The invention provides a cloud data deterministic deletion system and method based on ciphertext strong inseparability, and aims to solve the security problem after data deletion in a cloud storage system. According to the scheme, AONT (All-Or-Nothing-Transform) and a block encryption technology are combined, so that the ciphertext data has high inseparability, that is to say, original data cannot be recovered when any components of the ciphertext data are destroyed. A user hosts a secret key and part of ciphertext data to a trusted third party, and when a deletion operation is initiated, the trusted third party destroys part of the ciphertext data and the secret key, so that the irrecoverability of the data is ensured. Experimental results show that the scheme has obvious advantages in calculation performance, and excessive storage and bandwidth overhead cannot be introduced.

Description

Technical Field

[0001] The present invention relates to the field of cloud storage security technology, and specifically to a cloud data deterministic deletion system and method based on the strong indivisibility of ciphertext, which aims to solve the security problem of data after deletion in a cloud storage environment and ensure that deleted data cannot be recovered. Background Art

[0002] With the rapid development of cloud computing technology, cloud storage has become a vital platform for data storage and sharing. However, the trust between cloud storage service providers and users is limited, making data security a key concern for users. In particular, ensuring that cloud storage service providers or attackers cannot recover the plaintext of deleted data after data is deleted is a key issue that needs to be addressed in the cloud storage security field.

[0003] Existing technologies generally use the "encrypt data, destroy the key" approach to delete cloud data. However, this approach carries the risk of key leakage or brute-force cracking of ciphertext, and the deleted original data may still be recoverable. Furthermore, directly using common block cipher modes for encryption means that if an attacker cracks the key, obtaining a fragment of ciphertext is equivalent to leaking part of the plaintext. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention proposes a cloud data deterministic deletion system and method based on the strong indivisibility of ciphertext. By combining AONT (All-Or-Nothing-Transform) with block encryption technology, the ciphertext data is made strongly indivisible, meaning that destroying any component of the ciphertext data will render the original data irrecoverable. The technical solutions of the present invention include:

[0005] Data encryption module: This module performs block encryption on the original data to generate ciphertext data. The encryption process can use common block cipher algorithms such as AES to ensure the security of data during transmission and storage.

[0006] AONT Transformation Module: This module applies AONT transformation to the encrypted ciphertext data, making it highly indivisible. AONT transformation is achieved by obfuscating the original data itself, ensuring that destroying any portion of the ciphertext data renders the original data irrecoverable. This step is the core of the technical solution and significantly enhances data irrecoverability.

[0007] Data Escrow: Users entrust their keys and some ciphertext data to a trusted third party (TTP). The TTP is an entity independent of the cloud storage service provider and is responsible for destroying the keys and some ciphertext data when necessary. This step ensures the security of the keys and some ciphertext data while providing users with a convenient data deletion service.

[0008] Data Deletion Module: When a user wishes to delete data stored in the cloud, they send a deletion request to the TTP through the Data Deletion Module. Upon receiving the request, the TTP destroys the managed key and some ciphertext data and returns a deletion confirmation message to the user. This step ensures the definitive deletion of data and ensures that it is irrecoverable.

[0009] Data recovery verification module: To verify the effectiveness of data deletion, a data recovery verification module can be set up. This module attempts to recover the original data from the remaining ciphertext data. If recovery is unsuccessful, the data deletion operation is confirmed to be successful. This step provides a means of verifying the effectiveness of data deletion and enhances user confidence in the data deletion operation.

[0010] The present invention provides a system and method for deterministic deletion of cloud data based on the strong indivisibility of ciphertext. This system has the following beneficial effects:

[0011] 1. Ensure the irrecoverability of deleted data. By combining AONT with block encryption technology, the ciphertext data is made strongly indivisible, ensuring the irrecoverability of deleted data.

[0012] 2. Reduce computational overhead: Introducing data block scrambling technology reduces the number of cryptographic operations performed, improves resistance to ciphertext analysis, and reduces computational overhead.

[0013] 3. Enhance the credibility of data deletion operations: The credibility and security of data deletion operations are enhanced through the participation of a trusted third party and the setting of a data recovery verification module. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Encrypting test data

[0015] Figure 2 Decrypting the test image for data DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] Example:

[0018] With the widespread adoption of cloud computing and cloud storage technologies, more and more businesses and individuals are storing their data in the cloud. However, trust between cloud storage service providers and users has always been a key issue. In particular, ensuring that deleted data cannot be recovered after deletion has become a pressing technical challenge.

[0019] This embodiment aims to provide a method for deterministic deletion of cloud data based on the strong indivisibility of ciphertext, ensuring that after a user deletes data in cloud storage, the data cannot be recovered in any way.

[0020] Data encryption: Users first use the AES (Advanced Encryption Standard) algorithm to encrypt the original data in blocks to obtain the ciphertext data. The AES algorithm is a widely used symmetric encryption algorithm that can provide high security.

[0021] AONT Transform: After obtaining the ciphertext data, the user performs an AONT (All-Or-Nothing-Transform) on it. AONT is a data obfuscation technique that rearranges the ciphertext data and / or adds random noise, making the loss or damage of any part of the ciphertext impossible to decrypt. This makes it impossible for an attacker to extract useful information from the ciphertext, even if they obtain part of it.

[0022] Data hosting: Users upload AONT-transformed ciphertext data to the cloud storage service provider. At the same time, they entrust the key (used for AES encryption) and some ciphertext data (for example, the header or tail of the ciphertext data) to a trusted third party (TTP). The TTP is an entity independent of the cloud storage service provider and is responsible for storing and managing this sensitive information.

[0023] Key Management: TTP provides users with a secure key management environment, ensuring key security and availability. Users can query the key status at any time through TTP and request key destruction when necessary.

[0024] Data deletion request: When a user wishes to delete data stored in the cloud, they send a data deletion request to the cloud storage service provider through the TTP. The request includes the identifier of the data to be deleted (such as the file name or data ID) and the user's authentication information.

[0025] Data deletion: Upon receiving a data deletion request, the cloud storage provider verifies the user's identity and locates the corresponding data. The cloud storage provider then deletes the data from the storage medium. Simultaneously, the TTP destroys the stored key and some ciphertext data upon receiving the data deletion request. This prevents the cloud storage provider or an attacker from recovering the deleted data.

[0026] To verify the effectiveness of data deletion, users can choose to set up a data recovery verification process. The process includes:

[0027] Obtain the remaining ciphertext data (if any) from the cloud storage service provider.

[0028] Attempt to decrypt the remaining ciphertext data using the TTP's stored key (if it has not been destroyed).

[0029] If the decryption fails or no useful information can be extracted from the remaining ciphertext data, the data deletion operation is successful.

[0030] By using the deterministic cloud data deletion method based on strong ciphertext indivisibility provided in this embodiment, users can ensure that data in cloud storage cannot be recovered in any way after deletion. This significantly improves the security of cloud storage services and user trust. Furthermore, by introducing a trusted third party and AONT transformation technology, the risks of key leakage and data recovery are reduced.

[0031] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A cloud data deterministic deletion system and method based on strong ciphertext indivisibility, characterized by The following steps are involved: a) Encrypt the original data in groups to obtain ciphertext data; b) performing AONT transformation on the ciphertext data to obtain strongly indivisible ciphertext data; c) The user entrusts the key and part of the ciphertext data to a trusted third party; d) When a user initiates a deletion operation, the trusted third party destroys the managed key and part of the ciphertext data; e) Due to the strong indivisibility of ciphertext data, the destroyed ciphertext data cannot be restored to the original data.

2. The solution according to claim 1, characterized in that The block encryption adopts common block cipher working modes, such as code book mode, cipher block chaining mode, etc.

3. The solution according to claim 1, characterized in that The AONT transformation achieves strong indivisibility of ciphertext by obfuscating the original data itself.

4. The solution according to claim 1, characterized in that The trusted third party is an entity independent of the cloud storage service provider, which is used to host keys and some ciphertext data and destroy these data when the user initiates a deletion operation.

5. The solution according to claim 1, characterized in that It also includes a data block shuffling step to reduce the number of cryptographic operations performed, improve resistance to ciphertext analysis, and reduce computational overhead.

6. A device for implementing the solution of claim 1, characterized in that include: a) a block encryption module, used for performing block encryption on the original data; b) an AONT transformation module, configured to perform AONT transformation on the encrypted ciphertext data; c) Data hosting module, used to host the key and part of the ciphertext data to a trusted third party; d) Data destruction module, used to instruct a trusted third party to destroy the managed key and part of the ciphertext data when the user initiates a deletion operation.

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