System and Method for Restricting Access to a Computer System to Live Persons by Means of Semantic Association of Images

• US 20110191820A1
• Filed: 01/29/2010
• Published: 08/04/2011
• Est. Priority Date: 01/29/2010
• Status: Active Grant

• Current Assignee: Christopher Liam Ivey
• Original Assignee: Christopher Liam Ivey
• Inventors: Ivey, Christopher Liam
• Granted Patent: US 8,707,453 B2
• Time in Patent Office: Days
• US Class Current: 726/3
• CPC Class Codes: G06F 16/00 Information retrieval; Database structures therefor; File system structures therefor
• CPC Class Codes: G06F 21/36 by graphic or iconic representation
• CPC Class Codes: G06F 2221/2133 Verifying human interaction, e.g., Captcha
• CPC Class Codes: G06V 10/20 Image preprocessing

Abstract

A system and method for restricting access to a computer system, resource, or network to live persons, and for preventing the execution of automated scripts via an interface intended for human interaction.

When queried for access to a protected resource, computer system, or network, the system will respond with a challenge requiring unknown petitioners to solve a visual puzzle before proceeding, said puzzle consisting of a collection of apparently random objects, and exploiting the natural human impulse to form semantic or symbolic associations between images of objects.

The puzzle objects are assembled into a composite test image which is designed to frustrate machine interpretation but is still easily interpreted by a human being.

The subject of the test must either recognize a semantic or symbolic association between two or more objects, or isolate an object that does not belong with the others, indicating their selection with the pointing device on their local computer.

If the subject of the test succeeds in passing the test, they are granted access to the requested resource, computer system, or network. If not, they are invited to attempt the test again, up to a configurable maximum retests, after which time their request is simply ignored.

Claims

1. A system and method for restricting access to a computer system, resource, or network to live persons, and for preventing the execution of automated scripts via an interface intended for human interaction by means of a reverse Turing test that exploits the semantic, symbolic, and contextual associations humans instinctively form between images of objects, the system comprising:

a) A Challenge/Response Agent, resident on a server which creates and manages a session each time a protected resource is requested by an unknown Petitioning Agent, and which allows or denies access to the requested resource, system, or network based on the outcome of a test designed to determine whether or not the Petitioning Agent is a human user;

b) A Test Creation Engine, which creates a unique test for each verification session, based on a combination of configurable and random parameters;

c) An Images Database containing a plurality of random images;

d) A Semantic Context Database, containing a plurality of metadata associated with the unique ID of each image in the Images Database;

e) A Localization Engine, which creates a localized instruction string to guide the Petitioning Agent in completing the test;

f) An Image Composition Engine, which composes the images selected for a test into a single composite image, based on a combination of configurable and random parameters;

g) A Client-Side Test Application, which is executed on the local computer of the Petitioning Agent;

h) A Test Evaluation Engine, which examines the results returned by the Client-Side Test Application, and returns a pass or fail result to the Challenge/Response Agent.

2. A system according to claim 1, whereby the Challenge/Response Agent will respond to any request from an unknown Petitioning Agent for a protected resource, system or network by creating a test session and invoking the Test Creation Engine.

3. A system according to claim 1, whereby the Test Creation Engine will instantiate a new test which is randomly determined to be of either associative or exclusive logic, and request a single random key image ID from the Images Database.

4. A system according to claim 1, whereby if the test is associative the Test Creation Engine will query the Semantic Context Database for a collection consisting of the ID of a single image that is semantically associated with the key image and a plurality of image IDs that are not semantically associated;

and if the test is exclusive, the Test Creation Engine will query the Semantic Context Database for a collection consisting of the IDs of a plurality of images that are not semantically associated with the key image.

5. A system according to claim 1, whereby the Test Creation Engine will query the Localization Engine for a translated instruction string that will guide the user to draw a line joining the key image to an image that is semantically associated with it, (if the test is an associative test), or to circle the image that doesn'"'"'t belong, (if the test is an exclusive test).

6. A system according to claim 1, wherein the Test Creation Engine will pass the collection of image IDs and the localized instruction string to the Image Composition Engine, which will in turn create a composite test image.

7. A system according to claim 5, whereby the Image Composition will Query the Images Database for the images associated with a collection of image IDs, and assemble them into a single composite test image;

and render the localized instruction string on top of the composite test image.

8. A system according to claim 5, whereby the Image Composition Engine will create an image map that corresponds to the placement of the individual images contained in the composite test image.

9. A system according to claim 1, whereby the Challenge/Response Agent will transmit the composite test image to a Client-Side Test application, which can be embedded in an HTML document and is executed on the local computer of the Petitioning Agent.

10. A system according to claim 1, whereby the Client-Side Test application will instruct the Petitioning Agent to use the pointing device on their local computer to complete the instructions embedded in the composite test image.

11. A system according to claim 10, whereby the Client Side Test application will start recording the position of the pointing device on the Petitioning Agent'"'"'s local computer at intervals of a few milliseconds when it receives a press event from the pointing device, and will stop recording and transmit the collected position data back to the Challenge/Response agent when it receives a release event from the pointing device.

12. A system according to claim 1, wherein the Challenge/Response Agent passes the test data to the Test Evaluation Engine, which will plot the position data collected for the pointing device on the Petitioning Agent'"'"'s computer, and compare it to positions of the separate test sub images as recorded in the image map corresponding to the composite test image.

13. A system according to claim 12, wherein if the test is an associative test, the Test Evaluation Engine will return a pass result if the pointing device position data forms a line connecting the key image with the associated image without intersecting any of the other sub images in the composite test image;

and if the test is an exclusive test, the Test Evaluation Engine will return a pass result if the pointing device position data forms a line that intersects or encloses the key image without enclosing or intersecting any of the other sub images in the composite test image;

if the pass condition is not met, the Test Evaluation will return a failure result.

14. A system according to claim 1, whereby if the Test Evaluation Engine returns a pass result, the Challenge/Response Agent will allow the Petitioning Agent access to the requested computer system, resource, or network;

and if it returns a failure result, the Challenge/Response Agent will transmit a failure notification to the Petitioning Agent.

15. A system according to claim 1, wherein if the Petitioning Agent fails to pass a test, the Challenge/Response Agent will allow the Petitioning Agent to request a new test, up to a maximum number of retests;

after which, the Challenge/Response Agent will simply refuse all requests from the Petitioning Agent for the duration of cool-down time;

the maximum number of retests and cool-down interval being configurable by an administrator of the system.

16. A method for recording and retrieving the semantic, and symbolic associations human beings make between images of objects, said method comprising the creation of metadata consisting of a plurality of words and phrases which describe each image qualitatively, (or in terms of appearance and other qualities);

functionally, (or in terms of use and purpose and taxonomy); and

emotively, (or in terms of emotional state affected in the viewer);

said metadata being created and collected for each image in a collection by human operators.

17. The method of claim 16, wherein each image in a collection is examined by a human operator, and is recorded in a database, wherein it is associated with three collections of metadata, each containing a plurality of words and phrases, and which are separated by category as qualitative, functional, and emotive metadata.

18. A method for assembling a composite test image intended to frustrate machine interpretation, said method comprising the creation of a composite image created by superimposing:

a) A background image layer consisting of a randomly selected image sized to match the dimensions of the completed composite, said image being previously identified as suitable for the purpose by a human operator, and including an irregular pattern of repeating, contrasting elements, (such as blades of grass or bushes);

b) The test image layer, consisting of images selected for the test, each image being randomly rotated and positioned on the background in such a way that no images overlap or extend beyond the edge of the background layer;

c) A noise layer, consisting of a plurality of small, regular shapes which are randomly positioned on top of the background image and the test images.

19. The method of claim 18, wherein each test image is rotated randomly and alpha blended against the background image to a slight degree, said test image having a random opacity of between 80 and 100%.

20. The method of claim 18, wherein the noise layer consists of a plurality of small, regular shapes which vary in size between two configurable thresholds, and are random in colour;

the pixels of said shapes being blended at a very low alpha, and by value by multiplying, adding or subtracting the colour value from the underlying pixels;

the blend mode used and the alpha value at which it is applied would be random for each shape instance;

the thresholds for the size of each shape and the number of shape instances used being configurable by an administrator of the system.