How is the IV computed for notification messages in IKE Phase I? I know in phase II it's computed: "using the hash of a concatenation of the last Phase I CBC block concatenated and the message id in the ISAKMP header" (RFC 2409 Apendic B) However, I'm not really sure how to do it for Phase I when encryption is applied (messages 5 and 6) and an error is found. Is it explained somewhere? Toni