Abstract: In order to prevent bit combinations which are assigned to specific control characters from arising when ciphering characters, transmittable characters which consist of a part of the ciphered character and fill characters are generated from the ciphered characters. When the ciphered characters respectively consists of m binary characters, respectively small n binary characters from a sequence of ciphered characters are provided with (m-n) fill characters and combined to form the transmittable characters. The binary values of the fill characters are selected in such a manner that no undesired control characters occur within the transmittable characters and given specific sequence of transmittable characters.