Abstract: Computer-implemented methods for synchronizing data between a server and a client are provided. In one aspect, a method includes receiving a request from a client to synchronize data. The request includes a synchronization token that includes client recent synchronization signatures, each client recent synchronization signature representing a state of data synchronization on the client for a certain time period. The method also includes comparing each client recent synchronization signature with a corresponding server recent synchronization signature representing data on a server for the same time period. When the comparison indicates that the data on the client for the time period represented by the client recent synchronization signature is not synchronized with corresponding data on the server for the time period, then the method includes sending the data on the server for the time period to the client. Systems and machine-readable media are also provided.

Abstract: Embodiments of a computer system, a method, and a computer-program product (e.g., software) for use with the computer system are described. These embodiments may be used to evaluate a user request to regain control of an online account. For example, the user request may be submitted online using a web page, and may include information that establishes the user's identity or that substantiates that the user is the owner of the online account, such as a history of recent activities associated with the online account. This information may be evaluated by comparing it to stored information associated with the online account, such as a stored history of recent activities or one or more locations of a registered user when the registered user previously accessed the online account. After evaluating the user request, remedial action may be performed.