Time-varying sequenced image overlays for CAPTCHA

• US 8,397,275 B1
• Filed: 02/05/2009
• Issued: 03/12/2013
• Est. Priority Date: 02/05/2009
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Magdsick, Karl
• Primary Examiner(s): KYLE, TAMARA TESLOVICH
• Application Number:
  US12/366,592
• Time in Patent Office: 1,496 Days
• Field of Search: 726/3, 726/2, 726/21, 380/54, 380/200, 380/213, 380/255, 713/201, 713/202
• US Class Current: 726/2
• CPC Class Codes: G06F 21/31 User authentication
• CPC Class Codes: G06F 2221/2133 Verifying human interaction, e.g., Captcha

Abstract

Time-varying CAPTCHA tests are provided to distinguish a human user from a computer software agent in an online application. A test generator generates an original image and a set of (X,Y) positions. The (X,Y) positions can be a random or repeating sequence. The test generator then separates the original image to form a plurality of secondary images. The secondary images are configured to the (X,Y) positions and the original image so that when the secondary images are displaced over time responsive to the (X,Y) positions at least one of the (X,Y) position reveals the original image, or a portion thereof. A test program generator generates an executable program adapted for execution on a client device. The executable program is encoded with the (X,Y) positions and the secondary images, and configured to displace the secondary images over time responsive to the set of positions.

Claims

1. A computer program product comprising a non-transitory computer-readable storage medium having computer-executable program instructions embodied therein for configuring a computer system to execute:

a test generator, configured to;

generate an original image;

separate the original image into a plurality of secondary images;

generate a set of positions for the plurality of secondary images, the set including at least one position at which the secondary images overlap to form a composite image that reveals at least one portion of the original image, and at least one position at which the secondary images overlap to form a composite image that does not reveal any portion of the original image,

associate a CAPTCHA query and an answer with the secondary images; and

a test program generator configured to;

generate an executable program that is adapted for execution by a client device having a display, and encoded with the set of positions, the CAPTCHA query, the answer, and the executable program configured to displace on the display of the client device, the secondary images over time responsive to the set of positions.

2. The computer program product of claim 1, further comprising:

a test serving engine, configured receive a request for a test from a web browser to access a web server engine, send the secondary images and the executable program to a web browser responsive to the request, receive a response to the CAPTCHA query from the user, and analyze the response to determine if the response matches the answer.

3. The computer program product of claim 1, wherein the secondary images and the positions are configured to reveal the at least one portion of the original image at varying locations in the original image.

4. The computer program product of claim 1, wherein the secondary images and the positions are configured to reveal a plurality of portions of the original image at any one time.

5. The computer program product of claim 1, wherein the original image is an image of a word, phrase, or any human identifiable content.

6. The computer program product of claim 1, wherein the composite image is formed of a portion of each of a plurality of the secondary images.

7. The computer program product of claim 1, wherein the secondary images are semi-transparent animated images that mimic the effect of moving static images relative to one another.

8. The computer program product of claim 1, wherein the secondary images include at least one video clip that mimics the effect of moving static images relative to one another.

9. The computer program product of claim 1, wherein the positions and the executable program are configured to render the secondary images as images of geometric objects that periodically align to form the at least one composite image that reveals at least a portion of the original image.

10. The computer program product of claim 1, wherein the test generator is configured to generate the secondary images and the positions by generating one or more time-varying functions, zero or more static data sets, and a combining function, and from the time varying functions, the static data sets, and the combining function generate a time-varying sequence of images that periodically reveals the original image.

11. The computer program product of claim 2, wherein the test serving engine further comprises a counter to count a number of attempts at a correct response, and wherein the test serving engine is configured to allow a predetermined number of attempts at a correct response and then block the web browser from accessing the web server.

12. The computer program product of claim 2, wherein the test serving engine further comprises a user timer to determine an amount of time the user has spent in providing the response to a question, and wherein the test serving engine is configured to block the web browser from further accessing the web server after a predetermined amount of time.

13. The computer program product of claim 10, wherein the time-varying sequence of images is a random sequence.

14. The computer program product of claim 10, wherein the time-varying sequence of images is a repeating sequence.

15. A method executed on computer for generating tests for distinguishing a human user from a computer software agent in an online application, the method comprising:

generating an original image;

separating the original image into a plurality of secondary images;

generating a set of positions for the plurality of secondary images, the set of positions including at least one position at which the secondary images overlap to form a composite image that reveals at least one portion of the original image, and at least one position at which the secondary images overlap to form a composite image that does not reveal any portion of the original image;

associating a CAPTCHA query and an answer with the secondary images; and

generating an executable program, adapted for execution by a client device having a display, and encoded with the set of positions, the CAPTCHA query, the answer, and the executable program configured to displace on the display of the client device, the secondary images over time responsive to the set of positions.

16. The method of claim 15, further comprising:

sending the secondary images and the executable program to a client device;

receiving a response to the CAPTCHA query from the client device; and

analyzing the response to determine if the response matches the answer.

17. The method of claim 15, wherein the secondary images and the positions are configured to reveal the at least one portion of the original image at varying locations in the original image.

18. The method of claim 15, wherein the secondary images and the positions are configured to reveal a plurality of portions of the original image at any one time.

19. The method of claim 15, wherein the original image is an image of a word, phrase, or any human identifiable content.

20. The method of claim 15, wherein the composite image is formed of a portion of each of a plurality of the secondary images.

21. The method of claim 15, wherein the secondary images are semi-transparent animated images that mimic the effect of moving static images relative to one another.

22. The method of claim 15, wherein the secondary images include at least one video clip that mimics the effect of moving static images relative to one another.

23. The method of claim 15, wherein the positions and the executable program are configured to render the secondary images as images of geometric objects that periodically align to form the at least one composite image that reveals at least a portion of the original image.

24. The method of claim 15, wherein the secondary images and the positions are generated by one or more time-varying functions, zero or more static data sets, and a combining function, and from the time varying functions, the static data sets, and the combining function generate a time-varying sequence of images that periodically reveals the original image.

25. The method of claim 16, wherein the client'"'"'s response is blocked after a predetermined number of attempts at a correct response.

26. The method of claim 16, wherein the client'"'"'s response is blocked after a predetermined amount of time.

27. The method of claim 24, wherein the time-varying sequence of images is a random sequence.

28. The method of claim 24, wherein the time-varying sequence of images is a repeating sequence.

29. A computer program product comprising a non-transitory computer-readable storage medium having computer-executable program instructions embodied therein for configuring a computer system to generate tests for distinguishing a human user from a computer software agent in an online application, the program instructions for configuring the computer system to perform steps comprising:

generating an original image;

separating the original image into a plurality of secondary images;

generating a set of positions for the plurality of secondary images, the set of positions including at least one position that forms a composite image that reveals at least one portion of the original image, and at least one position that forms a composite image that does not reveal any portion of the original image;

associating a CAPTCHA query and an answer with the secondary images; and

generating an executable program, adapted for execution by a client device having a display, and encoded with the set of positions, the CAPTCHA query, the answer, and the executable program configured to displace on the display of the client device, the secondary images over time responsive to the set of positions.

30. The computer program product of claim 29, the steps further comprising:

sending the secondary images and the executable program to a client device;

receiving a response to the CAPTCHA query from the client device; and

analyzing the response to determine if the response matches the answer.

31. The computer program product of claim 29, wherein the secondary images and the positions are configured to reveal the at least one portion of the original image at varying locations.

32. The computer program product of claim 29, wherein the secondary images and the positions are configured to reveal a plurality of portions of the original image at any one time.

33. The computer program product of claim 29, wherein the original image is an image of a word, phrase, or any human identifiable content.

34. The computer program product of claim 29, wherein the composite image is formed of a portion of each of a plurality of the secondary images.

35. The computer program product of claim 29, wherein the secondary images are semi-transparent animated images that mimic the effect of moving static images relative to one another.

36. The computer program product of claim 29, wherein the secondary images include at least one video clip that mimics the effect of moving static images relative to one another.

37. The computer program product of claim 29, wherein the positions and the executable program are configured to render the secondary images as images of geometric objects that periodically align to form the at least one composite image that reveals at least a portion of the original image.

38. The computer program product of claim 29, wherein the secondary images and the positions are generated by one or more time-varying functions, zero or more static data sets, and a combining function, and from the time varying functions, the static data sets, and the combining function generate a time-varying sequence of images that periodically reveals the original image.

39. The computer program product of claim 30, wherein the executable program is further adapted to count the number of attempts at a correct response, allow a predetermined number of attempts at a correct response and then block the client device from accessing a web server.

40. The computer program product of claim 30, wherein the executable program is further adapted to determine an amount of time the client device has spent in providing the response to the query, and then block the client device from accessing a web server after a predetermined amount of time.

41. The computer program product of claim 38, wherein the time-varying sequence of images is a random sequence.

43. The method of claim 41, further comprising:

sending the secondary images and the executable program to a web browser;

receiving a response to the CAPTCHA query from a user; and

analyzing the response to determine if the response matches the answer.

42. A method executed on a computer for generating tests for distinguishing a human user from a computer software agent in an online application, the method comprising:

generating a plurality of original images;

separating the original images into a plurality of secondary images;

generating a set of positions, the set of positions including a plurality of positions, including at least one position at which the secondary images overlap to form a plurality of composite images that reveal at least several portions of the original images, and at least one position at which the secondary images overlap to form a composite image that does not reveal portions of any of the original images;

associating a CAPTCHA query and an answer with the secondary images; and

generating an executable program encoded with the set of positions, the CAPTCHA query, the answer, and the executable program configured to displace the secondary images over time responsive to the set of positions.