A method performed by a first computing device is disclosed. The method includes (a) establishing a proximity-based communications channel between the first computing device and a second computing device, one of the first device and the second device being a mobile device, (b) sending a request for authentication of identity of a remote entity from the first device to the second device, the remote entity being in possession of the second device, (c) receiving, at the first device, from the second device, an identity assertion that the remote entity is authentically identified by an identifier, the identity assertion's truth being conditional on a proximity-based condition, (d) verifying, at the first device, that the proximity-based condition is satisfied, and (e) in response to verifying, validating the identifier of the remote entity. An apparatus and computer program product for carrying out the method are also provided.