Abstract: An authentication system 100 includes an authentication server 10 and a service providing server 20 for providing a service. When a user requests authentication, the authentication server lets the user input login information, transmits the login information to the service providing server 20, and calculates a first hash value from the login information using a hash function. The service providing server 20 calculates a second hash value from the login information using the same hash function if the login information transmitted from the authentication server 10 matches information that is registered in advance. The authentication server 10 establishes a session with a terminal 30 if the first hash value and the second hash value match each other.

Abstract: To more effectively motivate a user to transmit information, an information processing system includes an information receiver that receives real-time information transmitted by a user terminal, a distributor that distributes the received real-time information to other predetermined user terminals, an analyzer that analyzes responses, from the other user terminals, to the distributed real-time information, an evaluator that evaluates the real-time information according to an analysis result, and an incentive provider that provides an incentive corresponding to the evaluation of the real-time information to a user who has transmitted the real-time information.