In an information processing system, a mobile phone obtains a setting program which makes security settings for ensuring security of communication by performing authentication with a communication destination on an unsecured communication link, from a registration server through a secure, first communication link; an information processing device executes the setting program obtained from the mobile phone to make security settings, communicates with a relay server through an unsecured, second communication link; the registration server receives access from the mobile phone through the first communication link, authenticates a user, and sends the setting program to the mobile phone; the relay server authenticates an information processing device in response to a connection request from the information processing device, makes security settings, and relays access from the information processing device to a communication network through the second communication link.