The disclosure relates to a method of authenticating content offered by a content source to a local device for displaying content. The method includes establishing a communication session between the content source and a browser executing at the local device, transmitting from the content source to the browser a validation page comprising a content authentication token which is a randomly generated one-time use only credential bound to the content source, and capturing the content authentication token from the browser by a verification application. The method also includes transmitting the authentication token to a validation service which determines whether the token is bound to a valid source of content and causing the content to be displayed on the local device if the token is bound to a valid source of content.