Abstract: A method and system for secure file sharing based on a domestic cryptographic algorithm including 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, combining the digest values 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; and receiving, by the file receiving user terminal B, the shared file F and then decrypting the shared file to obtain the file f.

Abstract: A security encryption method for computer files, and a security decryption method for computer files belong to the field of computer technology security and are used for solving the problem of data storage security. The encryption method and the decryption method are applied to a computer-readable storage medium and a computer. The computer sends a plaintext file or a ciphertext file to the computer-readable storage medium for executing an encryption or decryption operation, and then the computer-readable storage medium transmits the ciphertext file or the plaintext file to the computer. Both the encryption method and the decryption method are recorded in the computer-readable storage medium, such that a user only needs to possess the computer-readable storage medium; all data encrypted by the computer-readable storage medium cannot be decrypted by an illegal user; and all required critical keys do not need to be memorized by the user or stored by other means.