Announcing ZIP 224: Bringing Halo 2 to Zcash

Hi all, we posted two blogs this morning with our proposal to bring Halo to Zcash, removing trusted setup, making it a better platform on which to build on (ex. possible UDAs), and setting a solid foundation for growth.

Overview: Announcing ZIP 224: Bringing Halo 2 to Zcash - Electric Coin Company

Technical: Technical explainer: Halo on Zcash - Electric Coin Company

We look forward to the community’s thoughts and feedback.


This is awesome stuff!

So for User Defined Assets and Zk-Rollups;

What would you say the next steps are for getting those operational once Halo is deployed?

Would it be possible to get some sort of checklist for these so developers (and ZOMG/ZFND) can easily define what exactly would need to be done?


Great news, interesting reads, I’m partial to the old pasta curves myself (mainly due to my love of Italian food!)

I see a ZIP where sends to sapling pool will be disabled from pollard pool. Will sends to sapling pool be enabled from sprout pool? It is interesting that such a rules can be included in ZIP (while we get lot of push back for including disabling t2t sometime in future cc @secparam).

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We look forward to working with the ECC and the Zcash Community on implementing Halo: Zcash Community Call: Our Thoughts on Halo – The Zcash Foundation


@dontbeevil I disagree. I think the limiting transactions between shielded pools is a far easier thing to do and probably makes sense. The idea is once you upgrade, you upgrade. It simplifies things for code, for users, and ensures sprout and then sapling eventually go away.
Thats drastically different from removing a in use transaction type.

Though, if any of @daira or @str4d are here, we might want to think what happens if you upgrade and then downgrade wallets. Or move from a sapling supporting one to a hallo one that sucks and then try to move back. Seems you either can’t move your money back or loose privacy by moving through t.

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oops. I’m not proposing to stop users from moving to sapling from sprout because users might be more comfortable with Sapling than pollard (because its new?).

Oh yeah stoping sprout to sapling migrations seems bad unless it really simplifies deployment.

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Hey folks! At the December Arborist call, we heard a lot of good feedback about “Halo-in-Zcash” (a.k.a. “ZIP-224”), and as we mentioned, we’ve been working since then to address those and to prepare a more detailed proposal for the community to kick its tires at the next Arborist call on February 11.

We’ll have that information ready by then, but we don’t have it ready to present at the call this coming Thursday, so we’re not going to join the call, but we’ll listen to the recording after to collect any additional concerns or questions to include in our proposal.


great! We’ll post the video of the call probably on Friday for your consumption.

We are looking forward to the February Arborist call.


Hi @zooko , as promised, here is a summary of the call (the video and chat transcript are linked in the post): January 14 Community Call on Halo – The Zcash Foundation


Incredible turn-around time @antonie. Thanks for the summary!