Abstract: A user agent stores user information of a user and user information provided to a service provider server. When a user terminal registers the user in the service provider server, the user agent sends the user information already provided to the service provider server to the user terminal. When the user agent receives a provision permission of the user information from the user terminal, the user agent generates pseudo user identification information, a public key, and a private key, signs a service document of the service provider server, and sends the service document to the service provider server via the user terminal. When the signed service document is received, the user agent verifies the signature and sends user information to the service provider server.

Abstract: An information distribution history management system (10) includes a service user terminal (200) and a service provider server (300) that request an information distribution history management device (100) to make a record of provision in a case where personal information related to a user is provided to the service provider server (300). Also, the service provider server (300) requests the information distribution history management device (100) to make a record of receipt when the service provider server (300) receives the personal information. The information distribution history management device (100) stores records in response to requests and also searches the records. The records include identification information of the user of the service user terminal (200), identification information of the providing service provider server (300), and identification information of the receiving service provider server (300).

Abstract: A user agent stores a private key and a public key of a user, and user information (registered user information). The user agent receives from a user terminal a service document including identification information of a service provider server and a user information classification requested by the service provider server, and adds a signature to the service document by using the private key of the user. The user terminal receives the signed service document and transmits the signed service document to the service provider server. The user agent receives the signed service document from the service provider server, and verifies the signature and transmits back to the service provider server the user information of the user corresponding to the included user information classification.