Social Authentication Protocol for Mobile Phones

With a standard security token, the intruder needs the token and the PIN to masquerade as the user. In our protocol the theft of a single phone would not necessarily result in a security breach, even if the PIN is known to the intruder. To generate enough tokens the intruder needs to have N phones. Where N is the number of tokens required for authentication. Having a large N, maintains high security. However it makes authentication more difficult.