References

   [1] Federal Information Processing Standards Publication (FIPS PUB)
       46-1, Data Encryption Standard, Reaffirmed 1988 January 22
       (supersedes FIPS PUB 46, 1977 January 15).

   [2] ANSI X3.92-1981, American National Standard Data Encryption
       Algorithm, American National Standards Institute, Approved 30
       December 1980.

   [3] Federal Information Processing Standards Publication (FIPS PUB)
       81, DES Modes of Operation, 1980 December 2.

   [4] ANSI X3.106-1983, American National Standard for Information
       Systems - Data Encryption Algorithm - Modes of Operation,
       American National Standards Institute, Approved 16 May 1983.

   [5] ISO 8372, Information Processing Systems: Data Encipherment:
       Modes of Operation of a 64-bit Block Cipher.

   [6] ANSI X9.17-1985, American National Standard, Financial
       Institution Key Management (Wholesale), American Bankers
       Association, April 4, 1985, Section 7.2.

   [7] Voydock, V. L. and Kent, S. T., "Security Mechanisms in High-
       Level Network Protocols", ACM Computing Surveys, Vol. 15, No. 2,
       June 1983, pp. 135-171.

   [8] CCITT Recommendation X.509, "The Directory - Authentication
       Framework", November 1988, (Developed in collaboration, and
       technically aligned, with ISO 9594-8).

   [9] Kaliski, B., "The MD2 Message-Digest Algorithm", RFC 1319, RSA
       Laboratories, April 1992.

  [10] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, MIT
       Laboratory for Computer Science and RSA Data Security, Inc.,
       April 1992.

  [11] PKCS #1: RSA Encryption Standard, Version 1.4, RSA Data Security,
       Inc., June 3, 1991.

  [12] Linn, J., "Privacy Enhancement for Internet Electronic Mail: Part
       I: Message Encryption and Authentication Procedures", RFC 1421,
       DEC, February 1993.

  [13] Kent, S., "Privacy Enhancement for Internet Electronic Mail: Part
       II: Certificate-Based Key Management", RFC 1422, BBN, February
       1993.

  [14] Kaliski, B., "Privacy Enhancement for Internet Electronic Mail:
       Part IV: Key Certification and Related Services", RFC 1424, RSA
       Laboratories, February 1993.