My approach is to provide a full implementation of the solution for both problems (as described by the Project Gossamer comment above).

More specifically, I'm creating a generalized open source library (libgossamer), a WordPress core patch which consumes libgossamer (wp-gossamer.patch), and a standalone REST API server for anyone who wants to run a federated key server for their local WordPress installs to defer to (so not every WordPress site needs to maintain a copy of the entire ledger history forever).

In practice, it's a more opinionated alternative to HERD.

The decision to create a separate library that contains most of the plumbing needed is to make it easy to write simulation code for Gossamer instances that verify security proofs. (The Gossamer paper will be easier to write with a reference implementation available, and everyone interested can collaborate on verifying the experimental results as I develop it.)