Cryptographic Algorithm Implementation Requirements for Routing Protocols

The interior gateway routing protocols Open Shortest Path First version 2 (OSPFv2) [RFC2328], Intermediate System to Intermediate System (IS-IS) [ISO] [RFC1195] and Routing Information Protocol (RIP) [RFC2453] currently define Clear Text and Message Digest 5 (MD5) [RFC1321] algorithms for authenticating their protocol packets. There have recently been documents adding support of the Secure Hash Algorithm (SHA) family of hash functions for authenticating routing protocol packets for RIP [RFC4822], IS-IS [ISIS-HMAC] and OSPF [OSPF- HMAC]. To ensure interoperability between disparate implementations, it is imperative that we specify a set of mandatory-to-implement algorithms thereby ensuring that there is at least one algorithm that all implementations will have available. This document defines the current set of mandatory-to-implement algorithms to be used for the cryptographic authentication of these routing protocols as well as specifying the algorithms that should be implemented because they may be promoted to mandatory at some future time.