A hand-held device for authenticating a marking on an object, said marking exhibiting a viewing-angle dependent light reflection spectrum. The device includes an imager for receiving light from said object and generating image data that include spectrum information, a marking detector for detecting marking image data associated with said marking in said image data, a parameter evaluator for determining a value of a predetermined spectrum parameter based on spectrum information of at least a part of said marking image data, an angle estimator for determining a value of a viewing angle between said imager and said marking associated with a determined value of said spectrum parameter, and an authenticator arranged for making an authentication decision based on at least two spectrum parameter values and their associated viewing angle values.