APPARATUS AND METHOD FOR AUTHENTICATION USER USING CAPTCHA

Disclosed are an apparatus and method for user authentication using CAPTCHA. The disclosed user authentication apparatus comprises: a display control unit for performing a control operation such that a text and a plurality of images for CAPTCHA can be displayed on a terminal device; and an authentication unit for authenticating whether a user of the terminal device is a normal user or not by using at least one image selected as a correct answer to the text through the terminal device among the plurality of images, wherein the plurality of images includes one or more correct answer images, one or more wrong answer images and one or more dummy images, the authentication unit authenticates the user by using whether the correct answer image and the wrong answer image are included in the selected at least one image, and whether the dummy image is included in the selected at least one image is not used in the user authentication. [Reference numerals] (211) First storage unit; (212) Second storage unit; (213) Third storage unit; (220) Display control unit; (230) Authentication unit; (240) Terminal device; (AA,BB) Database unit