主权项 |
1. A method comprising:
by a verification authority associated with a web service, receiving a request to access the web service, wherein the request comprises data uniquely identifying a client device, wherein the request was received from a shared device, and wherein the shared device is configured for use by a plurality of users; by the verification authority, accessing a social graph of a user associated with the client device to determine whether one or more social-networking users have previously accessed the shared device; and by the verification authority, transmitting to the client device information indicating which of the social-networking users have previously accessed the shared device. |