Abstract: A communication device for performing encrypted communication with at least one further communication device in a communication network is provided. Advantageously, the device is adapted to communicate with a plurality of further communication devices. The communication device comprises a communication unit and a cryptographic unit. Moreover it comprises a key encryption key generator configured to generate at least one key encryption key jointly with the at least further communication device, using the communication unit. Also, it comprises a traffic encryption key generator configured to generate a traffic encryption key, specific to the communication device, for encrypting traffic data by the communication device. The cryptographic unit is preferably configured to encrypt the traffic encryption key using the at least one key encryption key. Moreover, the communication unit is preferably configured to transmit the encrypted traffic encryption key to the at least one further communication device.

Abstract: A communication device for encrypted transmission of information via unencrypted transmission paths has at least one loudspeaker, one microphone, one audio processing facility, one encryption facility, and one transmission facility. Information is encrypted by the encryption facility and transmitted via unencrypted transmission paths by the transmission facility by further communication instruments. Thus, flexible use on the basis of the various communication instruments which can be used for encrypted transmission is made possible.

Abstract: An approach is provided for operating a radio network, wherein the operating frequency is varied systematically according to an enciphered sudden-frequency-change scheme and retained only during a hop. Several hops are combined to form a service interval, a service window being arranged at a variable position within the service interval. Given hops for different functionalities (late traffic entry, break-in, hailing, late network entry) of the radio network are specified in the service window.

Abstract: A method of secure communication in which communication partners (A, B) in each case have a secret (S) and a public code (P), in which the communication partner (A) selects a random number (x) and the communication partner (B) selects a random number (y), in which a first partial code (Ax) is formed by the communication partner (A) and a second partial code (By) is formed by the communication partner (B) by using the public code (P) of the respective partner (B, A) and is transmitted to the respective other communication partner (B, A). A session code (gxy, gyx) is formed from the private random number (x, y), and the partial code (By, Ax) of the respective communication partner (B, A) while using the private secret code (S), the partial codes (Ax, By) and the session codes (gxy, gyx) being calculated in a fashion similar to the Diffie-Hellmann protocol.