Proxy Re-Encryption Key Conversion via Intermediary Server
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Solution Overview
Problem
In file sharing systems using proxy re-encryption schemes, updating keys leads to a significant load on users, particularly group managers, due to the need to decrypt and re-encrypt large amounts of data and re-create re-encryption keys, which is inefficient and inconvenient.
Innovation Solution
A data management device and system that includes a conversion key storage and re-encryption key conversion mechanism, allowing for the conversion of encrypted data and re-encryption keys using a conversion key generated from old and new private keys, reducing the need for users to manually decrypt and re-encrypt data, thereby minimizing user load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the group manager decrypts and re-encrypts all encrypted files with the new key, then the data can be updated to use the new key, but the load on the group manager becomes excessive and communication time becomes excessive
Solution Approach 1:
The patent introduces a server as an intermediary that automatically performs the re-encryption of encrypted files when the group manager updates their key. The server receives the encrypted files from the group manager, re-encrypts them using the new key, and returns the updated files without requiring the group manager to manually process each file. This intermediary approach eliminates the excessive load on the group manager while ensuring reliable key updates.
2Reliability
If the group manager downloads all encrypted files, decrypts them, re-encrypts with the new key, and re-uploads them, then the key update is complete, but the communication time becomes excessive
Solution Approach 1:
The server performs the re-encryption operation autonomously without requiring the group manager to manually download, decrypt, re-encrypt, and re-upload each file. The server receives the encrypted files and conversion key, automatically processes the re-encryption using the new key, and returns the updated files. This self-service approach significantly reduces the time required for key updates while maintaining completeness.
3Reliability
If the group manager manually processes each encrypted file during key update, then control over the process is maintained, but the ease of operation deteriorates due to the complex manual steps required
Solution Approach 1:
The server acts as an intermediary that handles the complex re-encryption operations automatically. The group manager simply needs to provide the encrypted files and conversion key to the server, and the server manages the entire re-encryption process, including receiving files, applying the new key, and returning updated files. This intermediary approach maintains process control through the server's automated management while dramatically improving ease of operation for the group manager.
4Reliability
If re-encryption keys are re-created for all users when the group manager updates their key, then the security is maintained, but the load on the group manager increases significantly
Solution Approach 1:
The server serves as an intermediary that automatically re-creates re-encryption keys for all users when the group manager updates their key. The server receives the conversion key from the group manager, generates the new re-encryption keys, and distributes them to users without requiring the group manager to manually create and distribute each key. This intermediary approach maintains security through proper key regeneration while significantly improving efficiency by eliminating manual key distribution.
Data Source
AI summary
A data management device according to an embodiment stores first encrypted data obtained by encrypting plain text data with a first public key of a first user device. The data management device stores a first re-encryption key for re-encrypting the first encrypted data without decrypting to obtain first re-encrypted data decryptable with a private key of a second user device. The data management device stores a conversion key generated from a first private key corresponding to the first public key and a second private key of the first user device. The data management device converts the first encrypted data into second encrypted data with the conversion key. The data management device The data management device converts the first re-encryption key into a second re-encryption key with the conversion key.