CAPTCHA PROVISION METHOD AND PROGRAM

• US 20150143495A1
• Filed: 01/06/2012
• Published: 05/21/2015
• Est. Priority Date: 01/06/2012
• Status: Active Grant

• Current Assignee: Capy, Inc.
• Original Assignee: Capy, Inc.
• Inventors: Okada, Mitsuo
• Granted Patent: US 9,667,612 B2
• Time in Patent Office: Days
• US Class Current: 726/7
• CPC Class Codes: G06F 21/31 User authentication
• CPC Class Codes: G06F 2221/2133 Verifying human interaction, e.g., Captcha
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

[Problem] To selectively provide, in accordance with a user terminal a CAPTCHA that can be easily executed by an operator of the user terminal. [Solution] A web server (11) determines the type of web browser running in a user terminal (13). An authentication server (12) decides a CAPTCHA execution program on the basis of the type of web browser that has been determined. The authentication server (12) executes the decided CAPTCHA execution program to generate problem data and correct answer data. The web server (11) provides the CAPTCHA to the user terminal (13) on the basis of the problem data. The authentication server (12) compares the correct answer data and answer data generated by the user terminal (13), and determines whether authentication has succeeded or failed.

Claims

1. A method whereby a server provides an authentication CAPTCHA to a user terminal in a computer network configured at least from the server and the user terminal which is provided with 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 in 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.

2. The CAPTCHA provision method according to claim 1, the server determining in the web browser determination step whether the web browser run in the user terminal is run in a personal computer or run in a mobile terminal, and deciding in the CAPTCHA deciding step to execute an image CAPTCHA execution program as the CAPTCHA execution program when having determined the web browser to be run in a mobile terminal;

the CAPTCHA execution step when an image CAPTCHA execution step is executed comprising;

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;

the authentication result determination step when the image CAPTCHA execution is executed being 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.

3. The CAPTCHA provision method according to claim 2;

in the authentication result determination step when the image CAPTCHA execution program is executed;

the server calculating the 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 the absolute value of the difference is less than the threshold stored in the server.

4. The CAPTCHA provision method according to claim 3, the image set and the correct answer data being generated by the server in the image deciding step;

and

the vertical and horizontal size of the plurality of images included in the image set being decided based on the type of web browser determined by the web browser determination step.

5. The CAPTCHA provision method according to claim 2, the image set including one image representing an animal/plant or a man-made object, and at least one image that either incorporates the animal/plant or man-made object, is attached to the animal/plant or man-made object, or represents something that is food for the animal/plant.

6. The CAPTCHA provision method according to claim 5, the animal/plant or man-made object being a human, a humanoid robot, a mammal other than a human, or a vehicle.

7. The CAPTCHA provision method according to claim 2, the image set including one image shown with part of a first original image missing, and at least one image that has a brightness value corresponding to the missing part and that restores the first original image by being placed in the missing part.

8. The CAPTCHA provision method according to claim 3, the image set including a first image and a second image, at least one of which has a secret image embedded in a visually indiscernible form;

the secret image being included in at least part of an image obtained by totaling the brightness values of the corresponding pixels of the first image and the second image in an overlapping area where the first image and the second image overlap each other when the first image and the second image are in a relative position shown by the correct answer data; and

the server outputting the total of the brightness values of the corresponding pixels of the first image and the second image in the overlapping area to the display screen as the brightness value of the overlapping area in the image display step.

9. The CAPTCHA provision method according to claim 8;

the first image being an image generated from a second original image, and also being an image subjected to zero or more of the following three processes;

an embedding process of embedding the secret image in the image by using a numerical value based on the brightness value of the secret image to convert the brightness value of the area where the secret image is embedded, compared to before the embedding of the secret image;

an inversion process of inverting the brightness value of the image; and

a semitransparency process of making the image semitransparent; and

the second image being an image generated from the second original image, and also being an image subjected to any processes that of the three said processes were not performed on the first image.

10. The CAPTCHA provision method according to claim 1, the computer network being the internet;

and

the server having a first server device for telecommunicating with the user terminal, and a second server device for executing at least the authentication result determination step by telecommunicating with the first server device.

11. A program run in a server in order for the server to provide an authentication CAPTCHA to a user terminal in a computer network configured at least from the server and the user terminal, which is provided with a display screen and input means, the program comprising:

a web browser determination function for causing the server to execute a process for determining the type of web browser run in the user terminal;

a CAPTCHA deciding function for causing the server to execute a process of deciding 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 function for causing the server to execute a process for executing the decided CAPTCHA execution program and causing the web browser of the user terminal to execute the CAPTCHA; and

an authentication result determination function for causing the server to execute a process 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.

12. A method whereby a server provides an authentication CAPTCHA to a user terminal in a computer network configured at least from the server and the user terminal, which is provided with a display screen and input means, the CAPTCHA provision method comprising:

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 area defined in the display screen;

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

an authentication result determination step in which the server determines whether or not the relative positions of the images when the answer input was received satisfy a condition stored in the server, the server determining that authentication has succeeded when the condition is satisfied, and determining that authentication has failed when the condition is not satisfied.

13. A program run in a server in order for the server to provide an authentication CAPTCHA to a user terminal in a computer network configured at least from the server and the user terminal, which is provided with a display screen and input means, the program comprising:

an image deciding function for causing the server to execute a process of deciding one image set having a plurality of images;

an image display function for causing the server to execute a process of displaying the plurality of images included in the decided image set in an image display area defined on the display screen;

an image movement function for causing the server to execute a process of putting image movement input and answer input from the input means into a state that can be received by the user terminal, and a process of moving at least one of the plurality of images relatively within the image display area on the basis of the received image movement input; and

an authentication result determination function for causing the server to execute a process of determining whether or not the relative positions of the images when the answer input was received satisfy a condition stored in the server, determining that authentication has succeeded when the condition is satisfied, and determining that authentication has failed when the condition is not satisfied.