[Plants] Re: I-D Action: draft-ietf-plants-merkle-tree-certs-06.txt

[David Benjamin <[e-mail]>]

Hi buds!

Here is a cutting of draft-06 from the main branch. Here's a copy of the
changelog. Implementations are starting to sprout, so things have shifted
to rooting out the last few issues in advance of a concrete target for the
first real deployments. Here's the changelog, reproduced from the appendix:

* Use 24-bit length prefix for MTCProof subtree signatures.
* Renamed MerkleTreeCertEntry, etc., structures to MTCLogEntry to be
consistent with MTCProof, shorter, and help disambiguate the many English
meanings of "entry".
* Fixed one of the accumulated test vectors to better reflect one of the
edge cases in subtree covering.
* Make empty subtrees valid, so the subtree covering function always
returns two subtrees.
* Add an informative reference to the MTC-TLOG profile (c2sp.org/mtc-tlog)
and mention it where tile-based logs are discussed.
* Clarify that a landmark consists of both a number and a tree size, and
that a landmark's subtrees share its landmark number.
* Give an exact procedure for selecting the landmark and covering subtree
when constructing a landmark-relative certificate.
* Prune the pruning discussion. It's really a property of the log serving
protocol and is better described in [MTC-TLOG] and [TLOG-TILES].
* Fix the maximum log index to account for also end being 48-bit.
* Discuss a potential overflow in the valid subtree definition.
* Describe how a party holding a standalone certificate can construct the
corresponding landmark-relative certificate itself.
* Added test vectors for subtree algorithms in larger trees.
* Align the experimental OID with the final one in the X.509 name
construction in using RELATIVE-OID directly.
* Lifted the tree hash into the MTC CA extension OID, so it can capture new
tree constructions more generally.
* Update for draft-ietf-tls-trust-anchor-ids-05, and spell out certificate
configuration explicitly.
* Define active landmarks around landmark expiry and put the expiry time in
the landmark format.
* Fix an interaction between landmark-relative certs and TLS
certificate_authorities.

A peony for your thoughts,

David

On Mon, Sep 21, 2026 at 4:51 PM <[e-mail]> wrote:

> Internet-Draft draft-ietf-plants-merkle-tree-certs-06.txt is now
> available. It
> is a work item of the PKI, Logs, And Tree Signatures (PLANTS) WG of the
> IETF.
>
>    Title:   Merkle Tree Certificates
>    Authors: David Benjamin
>             Devon O'Brien
>             Bas Westerbaan
>             Luke Valenta
>             Filippo Valsorda
>    Name:    draft-ietf-plants-merkle-tree-certs-06.txt
>    Pages:   104
>    Dates:   2026-09-21
>
> Abstract:
>
>    This document describes Merkle Tree certificates, a new form of X.509
>    certificates which integrate public logging of the certificate, in
>    the style of Certificate Transparency.  The integrated design reduces
>    logging overhead in the face of both shorter-lived certificates and
>    large post-quantum signature algorithms, while still achieving
>    comparable security properties to existing X.509 constructions and
>    Certificate Transparency.  Merkle Tree certificates additionally
>    admit an optional size optimization that avoids signatures
>    altogether, at the cost of only applying to up-to-date relying
>    parties and older certificates.
>
> The IETF datatracker status page for this Internet-Draft is:
> https://datatracker.ietf.org/doc/draft-ietf-plants-merkle-tree-certs/
>
> There is also an HTML version available at:
> https://www.ietf.org/archive/id/draft-ietf-plants-merkle-tree-certs-06.html
>
> A diff from the previous version is available at:
>
> https://author-tools.ietf.org/iddiff?url2=draft-ietf-plants-merkle-tree-certs-06
>
> Internet-Drafts are also available by rsync at:
> rsync.ietf.org::internet-drafts
>
>
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