Krypto - Funkfernschreiber 58 / KFF-58
Gretag, Dr. Edgar Gretener AG, Zürich
überarbeitet am 28.2.2013
Because of the Telecrypto 53 units "fell out of synchronisation" quite often when
the messages were transmitted over shortwaves, the Dr. E. Gretener developed an
improved machine which consisted of a printer module as in the ETK-R 50,
of a ciphering unit as in the Telecrypto 53 and a synchronisation module:
The Krypto - Funkfernschreiber 58 (Ciphering radio teletype system 58) consists of the keyboard and the printing system of the ETK with it's fourteen character elements. In contrast to the CCITT No.2 Baudot code, most characters are still discernible, if the transmission of one of the character steps did fail.
The ciphering process is done in the encryption unit, which is set atop the teleprinter unit. Only the encryption unit was classified as being "secret".
The KFF 58 comes also with the SPG (Schlüsselproduktionsgerät), which is nothing else then a mechanical password generator. It is used to generate a true random message key, so that the operators did not use standard passwords.
Because of the KFF 58 used the fourteen segment code, it cannot be used in conjunction with other ciphering equipment which uses the 7 element Baudot code. The KPP 58 has been withdrawn from troop use in 1991, the ciphering modules have been destroyed nearly completely, the teleprinter parts have been sold to the public as surplus.
© Martin Bösch 14.2.2013