An LSI Digital Encryption Processor (DEP)

  • R. C. Fairfield
  • A. Matusevich
  • J. Plany
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 196)


This paper describes an LSI digital encryption processor (DEP) for data ciphering. The DEP combines a fast hardware implementation of the Data Encryption Standard (DES) published by the National Bureau of Standards (PJBS) with a set of multiplexers and registers under the control of a user programmed sequencer. This architecture enables the user to program any of the DES modes of operation published by NBS. In addition, multiple ciphering operations and multiplexed ciphering operations using up to four different keys may be programmed and internally executed without any external hardware.

The DEP is designed as a standard microprocessor peripheral. This LSI device should reduce the current cost and simplify the process of encrypting digital data to a point where it is feasible to include a ciphering function in modems, terminals, and work stations. The ability to internally program cascaded ciphers should substantially increase the security of the DES algorithm and hence, the life of the encryption equipment.


Data Encryption Standard Cipher Block Chain Plaintext Block Federal Information Processing Standard Publication Master Port 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. [1]
    Federal Information Processing Standards Publication 46, “Data Encryption Standard,” January 15,1977, published by the National Bureau of StandardGoogle Scholar
  2. [2]
    Federal Information Processing Standards Publication 81, “DES Modes of Operation,” December 2, 1980, published by the National Bureau of Standards.Google Scholar
  3. [3]
    W. Diffie and M. E. Hellman, “Exhaustive Cryptanalysis of the NBS Data Encryption Standard,” Computer, June 1977.Google Scholar
  4. [4]
    S. Even and O. Goldreich, “On the Power of Cascade Ciphers,” Advances in Cryptology, Proceedings of Crypto 83.Google Scholar
  5. [5]
    Whitfield Diffie and Martin E. Hellman, “Privacy and Authentication to Cryptography”, Proceeding of the IEEE, Vol. 67, No. 3, March 1979.Google Scholar
  6. [6]
    Alan G. Konheim, “Cryptography: A Primer”, John Wiley and Sons, INC., 1981, chapter 6.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1985

Authors and Affiliations

  • R. C. Fairfield
    • 1
  • A. Matusevich
    • 1
  • J. Plany
    • 1
  1. 1.AT&T Bell LaboratoriesMorristownUSA

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