From the IETF's IPSEC Working Group:

Title : ISAKMP Key Recovery Extensions Author(s) : T. Markham Filename : draft-rfced-exp-markham-00.txt Pages : 13 Date : 31-Aug-98 This document describes the proposed approach for negotiating and exchanging key recovery information within the Internet Security Association Key Management Protocol (ISAKMP). ftp://ftp.ietf.org/internet-drafts/draft-rfced-exp-markham-00.txt