Method and system for authentication

PURPOSE: An authentication method and system are provided to increase security relate with user authentication, thereby being usefully applied to a cloud service system etc. CONSTITUTION: A D-server (100) comprises a user interface unit (110), a random key generation unit (120), a 2D bar code generation unit (130) and a bar code transmission unit (140). In the user interface unit, the user connecting to the D-server performs a normal user registration process by using the terminal of the user and receives various interfaces. The random key generation unit generates a random key which is used in order to perform authentication about the user. The 2D bar code generation unit generates a 2D bar code by encoding the random key generated by the random key generation unit. The bar code transmission unit transmits the 2D bar code to the terminal of the user and indicates the 2D bar code on a display device. [Reference numerals] (100) D- server (web server); (110) User I/F unit; (120) Random key generation unit; (130) 2D bar code generation unit; (140) Bar code transmission unit; (150) User ID/PW DB