File encryption method

The invention provides a file encryption method, which is used for solving the technical problem of low file encryption efficiency caused by low key selection efficiency in the existing file encryption method, and comprises the following implementation steps that: (1) an encryption party preprocesses a file F to be encrypted; (2) the encryption party generates a root key vector S; (3) the encryption party acquires a public vector H and a secret key set key; (4) the encryption party generates a ciphertext vector set C; (5) the encryption party generates a ciphertext file and a key file and sends the ciphertext file and the key file; and (6) the decryption party decrypts the ciphertext file C. According to the method, the encryption security is ensured based on the LWE difficulty problem in the second vector selection process, and meanwhile, the secret key is generated by randomly selecting the first vector and calculating the secret key parameter only through one-time vector multiplication in the secret key se