Abstract: A method and system of administering a CAPTCHA challenge comprising: providing a CAPTCHA challenge to the client computer, the CAPTCHA challenge comprising an image and browser code for displaying the image, the image comprising a character string in which a first sub string smaller than said character string corresponds to a solution to the CAPTCHA challenge and a second substring smaller than said character string corresponds to extra characters not part of the solution, displaying the image on the client computer wherein only the first substring is visible in the browser, receiving a response from the client computer, comparing the response with the second substring, and determining, if the response includes the second substring, that the client computer used a CAPTCHA bot or relay.

Abstract: A method of identifying if a web client has browser capabilities. An originating machine receives a web page request from the web client. The originating machine generates a page request id (PRID) and a script which, when executed by a web client with a browser, regenerates a PRID, and embeds the script in a response. The originating machine sends the response to the web client for the web client to process and, if the web client is capable, to execute the embedded script, thereby to regenerate a PRID, and to return the regenerated PRID to the originating machine. The originating machine compares the returned regenerated PRID with the generated PRID, a match indicating that the web client has browser capabilities.

Abstract: Embodiments of the present invention relate to a method of providing an automated public Turing test to a client display system. The method includes providing an image having a plurality of random characters, as well as providing a browser code to the client, whereby the browser code is adapted to restrict display of the image to only a predetermined portion of the image. The method further includes detecting a client response to receiving the predetermined portion of said image.