Patent ID: 8745733

Claim:
A method of performing a security check at a user computer on web page content downloaded to the user computer over the Internet, the method comprising: retrieving rating information for the web page from a web service over the Internet, the rating information including one or more content ratings and a first signature generated from the content, using a specified algorithm, at substantially the same time as the one or more content ratings were determined; processing the downloaded web page content using said specified algorithm to generate a second signature; comparing said first and second signatures and quantifying differences therebetween; determining if the quantified difference exceeds a threshold value and, if not, then trusting the received content rating(s) and, if yes, then reporting the result to said web service; responsive to receipt of a reported result at the web service, generating updated rating information for the web page and sending the updated rating information to the user computer; and receiving updated rating information at the user computer and handling the web page content in accordance with the content ratings contained in the updated rating information.