In accordance with an example embodiment of the present invention, a method comprising: receiving at least one request for generating a challenge from at least one device; generating the challenge with at least two components; transmitting component of the challenge to the at least one device; causing presentation of at least part of the challenge to at least two users; causing communication between said at least two users; and receiving at least two responses to the challenge from the at least one device. Related apparatus and computer program product are also described.
