Dynamic Key Derivation for Secure File Sharing
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Solution Overview
Problem
Existing data sharing solutions face security challenges as they require sharing public keys and encrypting data with private keys, which can lead to key leakage and data leakage due to outdated encryption keys.
Innovation Solution
A file sharing method that dynamically generates a first dynamic key for each target file, uses this key to generate a first private key and public key, encrypts a symmetric key and the file using these keys, and uploads the encrypted information to a cloud sharing end for secure sharing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing data sharing solution uses private key for encryption, then data can be shared, but security of private key cannot be guaranteed and data leakage may occur
Solution Approach 1:
The patent segments the encryption key management by introducing an intermediate key (first key) that is derived from the private key but not identical to it. The private key is segmented into multiple components including the first key, second key, and third key, where each serves a specific purpose. This segmentation prevents direct exposure of the private key while enabling secure data sharing operations.
Solution Approach 2:
The patent introduces an intermediate key (first key) that acts as a mediator between the private key and the encryption process. This intermediate key is used for actual data encryption and sharing operations, while the private key itself remains protected and is only used for generating the intermediate keys. This intermediary layer prevents direct exposure of the private key during data sharing.
2Ease of manufacture
If all files are encrypted with the same private key, then encryption process is simple, but data leakage may occur due to private key not being updated
Solution Approach 1:
The patent implements dynamic key management where the first key is updated periodically or based on specific conditions. The system transitions from static private key usage to dynamic key derivation, where multiple keys (first key, second key, third key) are generated from the private key at different times or for different purposes. This dynamic approach maintains security over time while preserving operational simplicity through automated key management.
Solution Approach 2:
The patent changes the encryption parameters by introducing multiple derived keys instead of using a single static private key. The first key, second key, and third key represent different parameter states derived from the same private key, allowing the system to adapt encryption parameters based on time, data type, or security requirements while maintaining the underlying private key security.
3Ease of operation
If public key is shared for decryption, then data accessibility is enabled, but private key security is compromised
Solution Approach 1:
The patent extracts the decryption functionality from the private key itself by deriving multiple keys (first key, second key, third key) from the private key. The private key's secret properties are extracted and used only for key generation, while the derived keys handle actual encryption and decryption operations. This separation allows public sharing of decryption capabilities without exposing the private key's core security properties.
Solution Approach 2:
The patent uses derived keys (first key, second key, third key) as intermediaries between the private key and the data encryption/decryption process. These intermediate keys enable public sharing for data accessibility while maintaining private key security, as the intermediate keys can be safely distributed without compromising the original private key.
Data Source
AI summary
The present disclosure discloses a file sharing method and system. The method includes: obtaining a target file and determining a first dynamic key corresponding to the target file; generating a first private key based on the first dynamic key and double private keys; selecting unpaired public and private keys, and generating a first public key based on the first dynamic key, the selected public and private keys; encrypting a symmetric key using the first public key to obtain a key ciphertext; encrypting the target file using the symmetric key to obtain a file ciphertext; signing the first dynamic key, the first public key, the key ciphertext and the file ciphertext using the first private key to obtain signature information; and uploading the first dynamic key, the first public key, the key ciphertext, the file ciphertext and the signature information to a cloud sharing end to share the target file.