Abstract: A method and a device are disclosed for the low-cost implementation even of high-performance encryption functions in an encryptor. The encryptor may be composed merely of PC software or the like, or of any other terminal/information system with integrated Vernam cipher which does not need to be supported by expensive crypto-hardware for the actual encryption process. The crypto-hardware is made either of a chipcard or a multifunctional PC interface adapter (e.g., PCMCIA module) with built-in special crypto-hardware. The encryptor, on the other hand, is a conventional personal computer, software or another terminal which, however, with the exception of the very simple Vernam cipher (e.g., EXOR), needs no further crypto-technology even for broad-band applications in software.