In recent years, more and more studies or industry products have conducted recognition to the physiological feature or behavioral expression which are peculiar to human body, and these techniques provide the optimum solution for the environment, which needs identity verification, access badges or high security. In this paper, by the skin color area segmentation and principal component analysis -PCA, the face images are transferred into important feature vectors as the key of encrypting the files, thus our system can judge the user's permission of assessing the files according to the different facial features of each person.