A number of security systems, from Chip-and-PIN payment cards to contactless subway and train tokens, as well as secure localization systems, are vulnerable to relay attacks. Encrypting the communication between the honest endpoints does not protect against such attacks. The main solution that has been oered to date is distance bounding, in which a tightly timed exchange of challenges and responses persuades the verier that the prover cannot be further away than a certain distance. This solution, however, still won't say whether the specic endpoint the verier is talking to is the intended one or notit will only tell the verier whether the real prover is nearby. Are there any alternatives? We propose a more general paradigm based on multichannel protocols. Our class of protocols, of which distance bounding can be modelled as a special case, allows a precise answer to be given to the question of whether the unknown device in front of the potential victim is a relaying attack...