Patent ID: 9667612
Date: 2017-05-30
CPC Classifications: G06F,H04L,Y04S

Claim:
1. A method whereby a server provides an authentication CAPTCHA to a user terminal in a computer network, the user terminal having a display screen and input means, the CAPTCHA provision method comprising: a web browser determination step in which the server determines the type of web browser run at the user terminal; a CAPTCHA deciding step in which the server decides one of a plurality of CAPTCHA execution programs for executing mutually different CAPTCHAs in the web browser of the user terminal on the basis of the determined type of web browser, the CAPTCHA execution programs being stored in the server; a CAPTCHA execution step in which the server executes the decided CAPTCHA execution program and causes the web browser of the user terminal to execute the CAPTCHA; and an authentication result determination step in which the server determines whether or not authentication has succeeded on the basis of answer data that the user terminal has generated according to the executed CAPTCHA, wherein the CAPTCHA execution step comprises: an image deciding step in which the server decides one image set having a plurality of images; an image display step in which the server causes the plurality of images included in the decided image set to be displayed in an image display from the display screen as defined by the web browser; and an image movement step in which the server puts image movement input and answer input from the input means into a state that the user terminal can receive, and causes at least one of the plurality of images to move relatively in the image display area on the basis of the received image movement input; and wherein the authentication result determination step is a step in which: the server determines whether or not the answer data indicating the relative position of the plurality of images when the answer input is received satisfies a condition stored in the server, the server determining that authentication has succeeded when the condition is satisfied and that authentication has failed when the condition is not satisfied, wherein the authentication result determination step further comprises: the server calculating a difference between the relative position of the plurality of images indicated by the answer data and the relative position indicated by correct answer data stored in the server, and the server determining whether or not the authentication has succeeded on the basis of whether or not an absolute value of the difference is less than a threshold stored in the server.