Abstract: An apparatus for the transmission end-enciphering and reception end-deciphering of information comprising an enciphering device arranged at the transmitter for receiving plain text in the form of information signal groups separated from one another by separation or partition signals. At the transmitter there is provided a controllable control circuit operatively connected with a key character-information storage. The control circuit, when activated, causing a change of the key character information entered by the key character-information storage to the enciphering device and due to such change replacing the separation signals between the information signal groups by control signals representative of the key character-information.