Hi folks, as mentioned on today's http://zcasharborist.org/ call, at ECC we're migrating all of our discussion about "Trailing Finality Layer" to this channel to ensure its development is open to any collaborators and to enable people to follow along closely if they'd like.
For background on "Trailing Finality Layer" ( aka TFL) our initial announcement of that approach was https://electriccoin.co/blog/the-trailing-finality-layer-a-stepping-stone-to-proof-of-stake-in-zcash/ . For the current state of the project, we have in-progress semi-inconsistent high level description here: https://electric-coin-company.github.io/tfl-book/
A big piece that's missing from the TFL book is that we've improved upon the "Snap-and-Chat" construction in the Ebb-and-Flow Protocols paper. That construction has a big flaw (or if not a direct flaw at least very important missing detail) about how to ensure transactions remain valid/coherent during "sanitization". We're developing an improvement that still achieves the Ebb-and-Flow properties while being safe/coherent for transaction semantics called Crosslink (largely thanks to @Daira Emma !).
So big picture next steps are to update the book contents to introduce Crosslink and describe the status of Crosslink R&D. As for Crosslink itself, the main remaining piece is to finish a security argument for Safety. Meanwhile, we're also starting on a simulator we can use to analyze security (such as simulating specific attacks). That project is here https://github.com/zcash/simtfl and is still a prototype that does not yet simulate crosslink or Zcash NU5.
The current draft documentation for Crosslink is here.
Suggested Improvement
I just posted a bunch of status/resource updates to the
Proof-of-Stakechannel on Zcash R&D discord, and all of that information needs to be consolidated into the book so we have a single URL people can see to glean all that info.Here's a paste of the contents to feed into a PR: