Domestic Cryptographic File Sharing Without Manual Key Distribution
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Solution Overview
Problem
Existing file sharing technologies face issues such as the need for users to manage and distribute encryption keys, leading to key leakage risks and inconvenience when sharing with multiple recipients.
Innovation Solution
A secure file sharing method using domestic cryptographic algorithms, including asymmetric SM2, symmetric SM4, and digest SM3 algorithms, where public and private key pairs are managed centrally, enabling encryption and decryption without direct key distribution, and incorporating signature verification and re-encryption mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the user A uses common sharing technology to encrypt the file and send the key to user B, then the file can be securely transmitted to a single recipient, but the user A needs to manage and distribute keys manually, increasing the risk of key leakage and reducing convenience when sharing with multiple recipients
Solution Approach 1:
The patent introduces a key management center as an intermediary that holds the private key and assists in key generation. When user A wants to share a file with user B, the key management center participates in generating a shared secret key without user A needing to manually create and distribute encryption keys. This mediator approach resolves the contradiction by maintaining security through centralized key management while improving operational convenience through automated key distribution.
Solution Approach 2:
The patent implements a key generation mechanism where the key management center automatically generates encryption keys based on user identities and file characteristics, eliminating the need for manual key creation and distribution. The system self-manages the entire key lifecycle including generation, distribution, and revocation, thereby improving ease of operation while maintaining security through automated processes.
2Reliability
If the user A encrypts the file multiple times for multiple recipients, then each recipient receives a securely encrypted file, but the encryption process becomes complex and inconvenient for the user A
Solution Approach 1:
The patent creates a universal encryption mechanism where a single encrypted file can be shared with multiple recipients simultaneously. The key management center generates multiple decryption keys from a single encryption process, allowing the same encrypted file to be securely distributed to any number of users. This multi-functional approach resolves the contradiction by maintaining security for multiple recipients while eliminating the need for separate encryption operations.
Solution Approach 2:
The patent implements preliminary key generation and distribution through the key management center before actual file sharing occurs. The system pre-establishes decryption capabilities for multiple recipients, so when user A wants to share a file, the encryption process is simplified because the key management infrastructure is already in place. This preliminary preparation reduces the complexity of the encryption process while maintaining security.
3Ease of operation
If the user A shares the encryption key with multiple people, then the file can be shared with multiple recipients, but the risk of key leakage increases significantly
Solution Approach 1:
The patent segments the encryption key management into multiple independent key components that are distributed to different users. Instead of sharing a single key with multiple people, the system generates multiple separate decryption keys, each tied to a specific recipient's identity. This segmentation resolves the contradiction by enabling convenient sharing with multiple recipients while minimizing key leakage risk, as compromising one key does not expose other keys or the master secret.
Data Source
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AI summary
A method and system for secure file sharing based on a domestic cryptographic algorithm belong to the field of computer technology security and are used for solving the problems of security and permission control when a user shares a file. The method for file sharing includes the following steps: registering, by a user, at a file sharing user terminal A and a file receiving user terminal B, and sending registration information of the user to a key management center; calculating, by the key management center, digest values of usernames a and b with a digest algorithm SM3, combining the digest values with a private key matrix to calculate private keys sa and sb of the user, and sending the private keys to the file sharing user terminal A and the file receiving user terminal B; specifying, by the user, a file f to be shared at the file sharing user terminal A, encrypting the file to generate a shared file F, and sharing the shared file with the file receiving user terminal B; and receiving, by the file receiving user terminal B, the shared file F and then decrypting the shared file to obtain the file f. The present invention has the beneficial effects of avoiding the problem of key leakage and ensuring the security during file transmission.