Image-based completely automated public turing test to tell computers and humans apart (CAPTCHA)

摘要

An image is selected responsive to receiving an access request for access to protected content. An access code is assigned to the image, and the image is partitioned into a plurality of image tiles. Each image tile comprises a code segment, which is a part of the access code. The image tiles are then scrambled into a scrambled version of the image and displayed to a user. The user rearranges the scrambled version of the image to reassemble the image, identifies a correct sequence for the code segments, and then enters the code segments in the correct sequence as a codeword. The codeword is matched against the assigned access code. If they match, the user is granted access to the protected content. Otherwise the person is denied access to the protected content.

主权项

1. A computer-implemented method comprising:
assigning an access code to an image of an object, wherein the image is stored in a memory, and is different than the access code assigned to the image; receiving an access request for access to protected content from a user device; and responsive to receiving the access request:
retrieving the image from the memory;partitioning the image into a plurality of image tiles;partitioning the access code assigned to the image into a plurality of access code segments;generating a scrambled version of the image comprising:
assigning an access code segment to each of the plurality of image tiles according to a predetermined sequence; andscrambling the plurality of image tiles into the scrambled version of the image;sending a challenge to the user device for display to a user, the challenge comprising the scrambled version of the image such that the scrambled version of the image can be rearranged at the user device to obtain the access code;receiving a challenge-response comprising a codeword from the user device; andcontrolling access to the protected content based on a comparison of the codeword received in the challenge-response to the access code associated with the image, wherein controlling access to the protected content comprises:
granting access to the protected content if the codeword received in the challenge-response matches the access code associated with the image; anddenying access to the protected content if the codeword received in the challenge-response does not match the access code associated with the image.