I have re-reviewed this document, primarily by examining the changes from the -15 version. The authors have added references to RFC 6622, which specifies some protocol elements that could in principle provide any needed security properties. These changes relegate most of my previous concerns to RFC 6622. Unfortunately, most of my concerns still apply to RFC 6622, which has already been approved as Standards Track. I am undecided as to whether the Area Directors should treat my concerns with RFC 6622 as reasons to block this document. It does appear to me that a number of security aspects of this protocol suite are deferred to possible future work. This may even be appropriate, depending on the risk profile of the likely deployments. It is not clear to me that RFC 6622 is implementable as written (are there multiple existing implementations?), because it seems that it leaves a number of things underspecified. As an example, although future specifications that register ICV (integrity check value) algorithms might resolve these ambiguities, RFC 6622 appears to make an underlying assumption that it is possible to decompose ICVs as: ICV-value = cryptographic-function(hash-function(content)) which is not in general possible. (HMAC is but one example of how this assumption is invalid.) In some cases where it is possible to make such a decomposition, such as encrypting a hash value using a symmetric cipher, RFC 6622 does not specify necessary parameters such as the cipher mode. (Also, producing a message authentication code by encrypting a hash value using a symmetric cipher can lead to forgeries.) RFC 6622 leaves key management issues unresolved. In the next to last paragraph of Section 23.2, the word "valid" should probably be "invalid": Failure to verify an ICV included can be used as a reason to reject an incoming message or packet as "valid", according to Section 12.1 of [RFC6130] should be Failure to verify an ICV included can be used as a reason to reject an incoming message or packet as "invalid", according to Section 12.1 of [RFC6130]