Diffie-Helman USM Key Management Information Base and Textual Convention (RFC2786)
Original Publication Date: 2000-Mar-01
Included in the Prior Art Database: 2019-Feb-10
Internet Society Requests For Comment (RFCs)
This memo defines an experimental portion of the Management Information Base (MIB) for use with network management protocols the Internet community. In particular, it defines a textual convention for doing Diffie-Helman key agreement key exchanges an set of objects which extend the usmUserTable to permit the use of DH key exchange in addition to the key change method. This memo defines an Experimental Protocol for the Internet community.
Network Working Group M. St. Johns Request for Comments: 2786 Excite@Home Category: Experimental March 2000
Diffie-Helman USM Key Management Information Base and Textual Convention
Status of this Memo
This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (2000). All Rights Reserved.
This document specifies an experimental MIB. Readers, implementers and users of this MIB should be aware that in the future the IETF may charter an IETF Working Group to develop a standards track MIB to address the same problem space that this MIB addresses. It is quite possible that an incompatible standards track MIB may result from that effort.
This memo defines an experimental portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it defines a textual convention for doing Diffie-Helman key agreement key exchanges and a set of objects which extend the usmUserTable to permit the use of a DH key exchange in addition to the key change method described in . In otherwords, this MIB adds the possibility of forward secrecy to the USM model. It also defines a set of objects that can be used to kick start security on an SNMPv3 agent when the out of band path is authenticated, but not necessarily private or confidential.
The KeyChange textual convention described in  permits secure key changes, but has the property that if a third-party has knowledge of the original key (e.g. if the agent was manufactured with a standard default key) and could capture all SNMP exchanges, the third-party would know the new key. The Diffie-Helman key change described here
St. Johns Experimental [Page 1]
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  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. 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...