RFC 2786 (rfc2786) - Page 2 of 20

Diffie-Helman USM Key Management Information Base and Textual Convention

RFC 2786                 Diffie-Helman USM Key                March 2000


   limits knowledge of the new key to the agent and the manager making
   the change.  In otherwords, this process adds forward secrecy to the
   key change process.

   The recommendation in [12] is that the usmUserTable be populated out
   of band - e.g. not via SNMP.  If the number of agents to be
   configured is small, this can be done via a console port and
   manually.  If the number of agents is large, as is the case for a
   cable modem system, the manual approach doesn't scale well.  The
   combination of the two mechanisms specified here - the DH key change
   mechanism, and the DH key ignition mechanism - allows managable use
   of SNMPv3 USM in a system of millions of devices.

   This memo specifies a MIB module in a manner that is compliant to the
   SNMP SMIv2[5][6][7].  The set of objects is consistent with the SNMP
   framework and existing SNMP standards and is intended for use with
   the SNMPv3 User Security Model MIB and other security related MIBs.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [16].

   This memo is a private submission by the author, but is applicable to
   the SNMPv3 working group within the Internet Engineering Task Force.
   Comments are solicited and should be addressed to the the author.

Table of Contents

   1 The SNMP Management Framework .................................   2
   1.1 Structure of the MIB ........................................   3
   2 Theory of Operation ...........................................   4
   2.1 Diffie-Helman Key Changes ...................................   4
   2.2 Diffie-Helman Key Ignition ..................................   4
   3 Definitions ...................................................   6
   4 References ....................................................  17
   5 Security Considerations .......................................  18
   6 Intellectual Property .........................................  19
   7 Author's Address ..............................................  19
   8 Full Copyright Statement ......................................  20

1.  The SNMP Management Framework   The SNMP Management Framework
   presently consists of five major components:

   o   An overall architecture, described in RFC 2271 [1].

   o   Mechanisms for describing and naming objects and events for the
       purpose of management. The first version of this Structure of
       Management Information (SMI) is called SMIv1 and described in STD



St. Johns                     Experimental