Patents Represented by Attorney, Agent or Law Firm Marica L. Doubet
  • Method and apparatus for advanced symmetric key block cipher with variable length key and block
    Patent number: 6243470
    Abstract: A method and apparatus for an advanced symmetric key cipher for encryption and decryption, using a block cipher algorithm. Different block sizes and key sizes are supported, and a different sub-key is used in each round. Encryption is computed using a variable number of rounds of mixing, permutation, and key-dependent substitution. Decryption uses a variable number of rounds of key-dependent inverse substitution, inverse permutation and inverse mixing. The variable length sub-keys are data-independent, and can be precomputed.
    Type: Grant
    Filed: February 4, 1998
    Date of Patent: June 5, 2001
    Assignee: International Business Machines Corporation
    Inventors: Don Coppersmith, Rosario Gennaro, Shai Halevi, Charanjit S. Jutla, Stephen M. Matyas, Jr., Mohammed Peyravian, David Robert Safford, Nevenko Zunic