Data security protection method and data security protection device

The invention relates to a data security protection method and a data security protection device for protecting data security in a computer memory. The method comprises the following steps that: while starting computer equipment, a security module respectively distinguishes and authenticates a user identity and an encryption module, after passing through the distinguishing and the authentication, the security module transmits a data key to the encryption module, in the following use, the encryption module encrypts the memory data for protection, and if the distinguishing and the authentication are not passed, the computer cannot be started. The device comprises the security module and the encryption module, which are arranged in computer equipment, such as a PC host, a PDA, a mobile phone, a PMP or a digital photo frame and the like, and are connected with each other. The method and the device implement the transparent encryption for the memory data of computer equipment and the distinguishing of user identity, and simultaneously, separately store a key and an encryption algorithm, thereby implementing higher security.