Abstract: The securing of a telephone link between the two subscriber sets is established on the basis of encryption keys transmitted over the service channel (D) of the ISDN network whether the link be established on the switched telephone network (PSTN) or on the Internet network (NSTN). A server verifies the identifiers of the subscriber taps (PA1, PA2) and stores the encryption keys.

Abstract: Method and system for data communications between a first user station of a first network and a second user station of a second network via a network of the Internet type, in which, after an access terminal has obtained a public address intended for a communication between the first user station and the second user station, the access terminal is connected to the administrator, the administrator supplies the access terminal with connection data and supplies addressees with the connection data and the public address, and the access terminal establishes a communications tunnel with the second user station or with an access terminal of the second user station, then a communication with the second user station.

Abstract: A telephone link comprises two network terminals to which two subscriber sets are respectively connected, two subscriber lines respectively linking the two network terminals to two line terminals respectively located at two local switching centers mutually linked by a switched telephone network, the network terminal and the line terminal of at least one of the subscriber lines being respectively equipped with one network encryption/decryption means and with one line encryption/decryption means wherein information exchanged between the two subscriber sets is encrypted, at least on one of the two subscriber lines which is connected to the respective network and line encryption/decryption means, on the basis of at least one encryption key generated by the network encryption/decryption means or by the line encryption/decryption means, and varying temporally in pseudo-random fashion by the network encryption/decryption means or by the line encryption/decryption means, the information exchanged between the two subs