Provided are an encrypted transmission method and a data storage system. The method includes the following. Multiple random data blocks and an encryption table are read from a storage device. A logical operation is performed on the random data blocks according to the encryption table to obtain encrypted information. Key information is encrypted according to the encrypted information to obtain encrypted key information. The key information is used to encrypt or decrypt data transmitted between a host system and the storage device. The encrypted key information is transmitted to the storage device.