Patents by Inventor Paul Norman Prentice

Paul Norman Prentice has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 3958081
    Abstract: A device for ciphering message blocks of data bits under control of a cipher key. The cipher device performs an enciphering process for each message block of data by carrying out a predetermined number of iteration operations in the first of which a first half of the message block of data bits is first expanded by duplicating predetermined ones of the data bits. The data bits of the expanded message block are combined by modulo-2 addition with an equal number of cipher key bits, selected in accordance with an arbitrary but fixed permutation, to produce a plurality of multi-bit segments forming the arguments for a plurality of different nonlinear substitution function boxes. The substitution boxes perform a plurality of nonlinear transformation functions to produce a substitution set of bits which are equal in number to the number of data bits in the first half of the message block. The substitution set of bits is then subjected to a linear transformation in accordance with an arbitrary but fixed permutation.
    Type: Grant
    Filed: February 24, 1975
    Date of Patent: May 18, 1976
    Assignee: International Business Machines Corporation
    Inventors: William Friedrich Ehrsam, Carl H. W. Meyer, Robert Lowell Powers, Paul Norman Prentice, John Lynn Smith, Walter Leonard Tuchman