RFC 1824 (rfc1824) - Page 2 of 21

The Exponential Security System TESS: An Identity-Based Cryptographic Protocol for Authenticated Key-Exchange (E

RFC 1824                          TESS                       August 1995


   5.  Multiple SKIAs . . . . . . . . . . . . . . . . . . . . . . . . 15
       5.1.  Unstructured SKIAs . . . . . . . . . . . . . . . . . . . 15
       5.2.  Hierarchical SKIAs . . . . . . . . . . . . . . . . . . . 16
       5.3.  Example: A DNS-based public key structure  . . . . . . . 18
   Security Considerations  . . . . . . . . . . . . . . . . . . . . . 19
   References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 21

1.  Introduction and preliminary remarks

   This RFC describes The Exponential Security System TESS [1].  TESS is
   a toolbox set system of different but cooperating cryptographic
   mechanisms and functions based on the primitive of discrete
   exponentiation. TESS is based on asymmetric cryptographical protocols
   and a structure of self-certified public keys.

   The most important mechanisms TESS is based on are the ElGamal
   signature [2, 3] and the KATHY protocols (KeY exchange with embedded
   AuTHentication), which were simultaneously discovered by Guenther [4]
   and Bauspiess and Knobloch [5, 6, 7].

   This RFC explains how to create and use the secret and public keys of
   TESS and shows a method for the secure distribution of the public
   keys.

   It is expected that the reader is familiar with the basics of
   cryptography, the Discrete Logarithm Problem, and the ElGamal
   signature mechanism.

   Due to the ASCII representation of this RFC the following style is
   choosen for mathematical purposes:

   -  a  ^  b  means the exponentiation of a to the power of b, which is
      always used within a modulo context.

   -  a[b] means a with an index or subscription of b.

   -  a = b means equality or congruency within a modulo context.

1.1.  Definition of terms/Terminology

   Key pair

      A key pair is a set of a public and a secret key which belong
      together.  There are two distinct kinds of key pairs, the SKIA key
      pair and the User key pair. (As will be shown in the section about
      hierarchical SKIAs, the two kinds of keys are not really distinct.
      They are the same thing seen from a different point of view.)



Danisch                      Informational