http://www.rfc-editor.org/rfc/rfc5709.txt
RFC 5709: OSPFv2 HMAC-SHA Cryptographic Authentication, M. Bhatia, V. Manral, M. Fanto, R. White, M. Barnes, T. Li, R. Atkinson2009-10-01T23:00:00-00:00This document describes how the National Institute of Standards and Technology (NIST) Secure Hash Standard family of algorithms can be used with OSPF version 2's built-in, cryptographic authentication mechanism. This updates, but does not supercede, the cryptographic authentication mechanism specified in RFC 2328. [STANDARDS-TRACK]