1
Horst Feistel: Stream/block cipher crytographic system. International Business Machines Corporation, Roy R Schlemmer Jr, February 16, 1982: US04316055 (195 worldwide citation)

The system disclosed comprises a dual function cryptographic system capable of operating in either a stream or block cipher mode. Further, with minimal alteration the system is capable of performing either encoding or decoding functions. The system requires three inputs, the first of which is the ra ...


2
Willard G Bouricius, Horst Feistel: High security system for electronic signature verification. International Business Machines Corporation, Roy R Schlemmer Jr, April 20, 1982: US04326098 (108 worldwide citation)

The system provides both electronic signature and message verification with a minimum of excess coding information on an instantaneous basis and is easily restartable in a store and forward environment. The system is based on the concept of a vault or central authority. The vault is in essence a phy ...


3
Horst Feistel: Key controlled block-cipher cryptographic system employing a multidirectional shift matrix. International Business Machines Corporation, Roy R Schlemmer Jr, March 25, 1980: US04195200 (35 worldwide citation)

A cryptographic system for enciphering a block of binary data under the control of a unique key consisting of a set of binary symbols. A clear message represented in binary data format is transformed into a cipher message (and vise versa) by operating on blocks of clear information utilizing the ope ...


4
Horst Feistel: Variant key matrix cipher system. International Business Machines Corporation, Victor Siber, Roy R Schlemmer Jr, March 25, 1980: US04195196 (19 worldwide citation)

This is a cipher system for enciphering a stream of binary data by means of a product cipher. A clear message represented in a binary data format is transformed into a cipher message by operating on each bit of clear information with a complex modulo-two addition function. This function is dependent ...


5
Horst Feistel: Variant key matrix cipher system. International Business Machines Corporation, Roy R Schlemmer Jr, June 1, 1982: USRE030957

This is a cipher system for enciphering a stream of binary data by means of a product cipher. A clear message represented in a binary data format is transformed into a cipher message by operating on each bit of clear information with a complex modulo-two addition function. This function is dependent ...