A server comprising: a notification reception unit that receives information transmitted and received using a first communication when the first communication is performed between a provider terminal device related to a provider of a product or a service and an evaluator terminal device related to an evaluator of the product or the service, said information being received from the provider terminal device; a sorting specification unit that specifies at least one of: reliability sorting indicating a reliability of the provider of the product or the service, security sorting of the provider terminal device, and security sorting of the evaluator terminal device, based on identification information for the provider terminal device and identification information for the evaluator terminal device included in the information transmitted and received using the first communication; a link authentication unit that specifies a link authentication method of confirming a state of a second communication performed between the provider terminal device and the evaluator terminal device based on the sorting specified by the sorting specification unit, and performs a process related to the link authentication using the specified method; and an evaluation information reception unit that receives evaluation information regarding the product or the service which is transmitted and received using the second communication having undergone the link authentication, the evaluation information being received from the provider terminal device. a notification reception unit that receives information transmitted and received using a first communication when the first communication is performed between a provider terminal device related to a provider of a product or a service and an evaluator terminal device related to an evaluator of the product or the service, said information being received from the provider terminal device; a sorting specification unit that specifies at least one of: reliability sorting indicating a reliability of the provider of the product or the service, security sorting of the provider terminal device, and security sorting of the evaluator terminal device, based on identification information for the provider terminal device and identification information for the evaluator terminal device included in the information transmitted and received using the first communication; reliability sorting indicating a reliability of the provider of the product or the service, security sorting of the provider terminal device, and security sorting of the evaluator terminal device, based on identification information for the provider terminal device and identification information for the evaluator terminal device included in the information transmitted and received using the first communication; a link authentication unit that specifies a link authentication method of confirming a state of a second communication performed between the provider terminal device and the evaluator terminal device based on the sorting specified by the sorting specification unit, and performs a process related to the link authentication using the specified method; and an evaluation information reception unit that receives evaluation information regarding the product or the service which is transmitted and received using the second communication having undergone the link authentication, the evaluation information being received from the provider terminal device.