To solve a problem that it is possible to acquire other information inside a server based on information on a folder name, a file name, a program name, and the like, inside the information providing device, since these pieces of information are described in URL used on the Internet.

A communication means for the URL and the server name are not encrypted, but the portions of the folder name, the file name, the program name, and the like, of the URL are encrypted. Because the folder name, the file name, the program name, and the like, can be hidden to a content viewer by performing encryption processing for the URL like the above, it is made extremely difficult for a third party to acquire the other information by speculating from the content of the URL. For the encryption of the URL, the URL encryption device is used, and for the decryption of the URL, the URL decryption device is used.