A user authentication scheme not requiring secrecy in the computer

ABSTRACT

In many computer operating systems a user authenticates himself by entering a secret password known solely to himself and the system. The system compares this password with one recorded in a Password Table which is available to only the authentication program. The integrity of the system depends on keeping the table secret. In this paper a password scheme is presented which does not require secrecy in the computer. All aspects of the system, including all relevant code and data bases, may be known by anyone attempting to intrude. The scheme is based on using a function H which the would-be intruder is unable to invert. This function is applied to the user's password and the result compared to a table entry, a match being interpreted as authentication of the user. The intruder may know all about H and have access to the table, but he can penetrate the system only if he can invert H to determine an input that produces a given output. This paper discusses issues surrounding selection of a suitable H. Two different plausible arguments are given that penetration would be exceedingly difficult, and it is then argued that more rigorous results are unlikely. Finally, some human engineering problems relating to the scheme are discussed.

REFERENCES

• 1: Feistel, Horst. Cryptographic coding tbr data-bank privacy. Res. Rept. RC-2827. T. J. Watson Res. Lab., IBM, 1970.
• 2: Feistel, Horst. Cryptography and computer privacy. Scientific American 228 (May 1973), 15-23.
• 3: Kahn, David. The Code Breakers. Macmillan, New York, 1967.
• 4: Donald E. Knuth, The art of computer programming, volume 2 (3rd ed.): seminumerical algorithms, Addison-Wesley Longman Publishing Co., Inc., Boston, MA, 1997
• 5: Purdy, George. Security code. U. of Illinois, Center for Advanced Computation, 1973.
• 6: Shannon, Claude E. Communication theory of secrecy systems. Bell System Technical J. 28 (1949), 656-715.
• 7: J. L. Smith , W. A. Notz , P. R. Osseck, An experimental application of cryptography to a remotely accessed data system, Proceedings of the ACM annual conference, August 01-01, 1972, Boston, Massachusetts, United States [doi>10.1145/800193.569930]
• 8: M. V. Wilkes, Time Sharing Computer Systems, Elsevier Science Inc., New York, NY, 1975

INDEX TERMS

Primary Classification:
  D. Software
  D.4 OPERATING SYSTEMS
      D.4.6 Security and Protection
          Subjects: Authentication

Additional Classification:
  E. Data
  E.3 DATA ENCRYPTION

  K. Computing Milieux
  K.6 MANAGEMENT OF COMPUTING AND INFORMATION SYSTEMS
      K.6.5 Security and Protection (D.4.6, K.4.2)
          Subjects: Authentication

General Terms:
Management, Performance, Security

Keywords:
authentication, cryptology, one-way encryption, operating system security, passwords, security