[Grant Update] Zcash Shielded Assets Monthly Updates

Hi all, I decided to create a new thread, to separate the main ZSA Proposal from the actual work done.

We promised the community and the MGRC to post monthly updates. This is the first update, after a month of work! Expect all updates to come around the 15th of the month, though we plan to have more interactive discussions.

This first month has been super exciting, and we have several updates on the project:

  1. We have hired Vivek and Shahaf, two cryptography engineers to join the ZSA team. I have never seen such a fast onboarding onto the Zcash protocol (quite complex one!) - they are in their second week and diving into the deeper details of how to make the values balance with the binding signature for a multi-asset version.

  2. We had a great discussion in one of the latest Arborist calls with the ECC and ZF technical teams, we outlined several options for how to make the Issuance happen best (more on this below). It is important for us to share the technical details with the community, but especially with these two teams who make the core dev team of the protocol.

  3. We are getting really close to releasing a first draft of the transfer ZIP (please stay tuned). For the first version we decided to not fix the specific number of types of assets allowed per transaction, as we are studying the concrete circuit used with Halo2 and its limitations.

  4. In terms of the issuance mechanism, we will also soon release a preliminary document to outline our concrete approach so we can get the full review of the community before writing the ZIP. We are considering using the “spend” part of the Orchard Action to issue assets transparently (with a potential private extension) and the “output” part to burn assets transparently. For now, we will focus on the simple functionality of not limiting the amount of issuance calls allowed by an issuer, and we leave the importing / wrapping of assets to be handled by a trusted entity (while making everything verifiable). Stay tuned for the full doc!

In terms of the timeline, we are doing great with time since we have two more months to accomplish the first two milestones of the project (transfer ZIP + issuance ZIP).
We recommend everyone to join the next Arborist call, next Thursday to hear more!
We will also be hosting a separate community call to discuss the issuance mechanism in a live discussion.

Thank you all!!
to the zsa-moon <3

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Very exciting! Welcome to Vivek and Shahaf from the depths of the Zcash Specification :smiley:

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OMG, a “zsa-moon” token should definitely be the first on-chain issuance :joy:

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jajaja maybe we should
want to be the issuer??

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I’m in. Max issuance divided evenly amongst valid addresses memo’d to me :astronaut::rocket::full_moon_with_face:.

I think there should be some kind of sybil resistance to this mechanism. I propose a shielded memo with a proof of forum account :stuck_out_tongue:

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Very exciting!

Is NFT issuance possible with ZSA? Is that out-of-scope?

@dontbeevil That’s a good question. As far as I understand it each token is fungible. Asset types are not.

@LeCryptoMath how many bytes will the asset type ID be? I imagine rather then needing NFTs to represent art/collectibles we could issue a seperate new ZSA type for each seperate piece of art/collectible.

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Dear Zcash community,

We are super excited to share with you the first DRAFT versions of the two ZIPs that cover the ZSA protocol, which @naure @PabloK @shahafn @vivek and myself worked on for the past months with the help of @daira @str4d and @tromer:

These ZIPs have been in the works for the past two months and we have interacted with the community, the ECC and the ZF developers to ensure the compatibility, usability, privacy & security and elegancy of the protocol.

You can find here the three different calls that we had discussing these ZIPs

A short description

Issuance

As our MVP, the issuance mechanism is transparent, and enables several interesting applications of issuance on Zcash. We have designed a protocol that enables batch issuance for finite or infinite supply of assets. It allows for NFT-style issuance, and is off-chain extensible to allow for bridges to be built. In terms of security, we provide the ability for the chain to track the total supply of any token, as well as for individuals to revoke the issuance of an asset id in case of compromise.

Transfer

In terms of the transfer mechanism, we have designed a circuit that ensures that old-style ZEC Orchard notes can be used as-is within the ZSA protocol, making the transactions totally indistinguishable from the Orchard transactions. This means that we have backward-compatibility and in terms of upgrade, we will not have to create a turnstile.

The transfer has been reviewed to be secure, albeit lacking of an actual security proof, which we hope to at least sketch.

Burn

In order to properly support an end-to-end ZSA protocol, we designed a very elegant burning mechanism. We will use the inherited format of the shielding/unshielding of ZEC in the Orchard protocol (that uses the transparent ValueBalance) in order to confirm that some amount of a given asset has been burnt and is unspendable. We define purely the protocol for burning, but we do not provide a specific implementation of how a bridge should be built, as there could be several ways to accomplish the bridge (the main question is how to transfer data to the bridge operator).

Discussion points

Comments

These ZIPs are in DRAFT mode and will definitely see some changes in the months to come, both as we receive feedback from the community and core developers, as well as changes that arise in the implementation process. We have started working on a prototype of these designs in order to have initial tests.

We welcome any comments and questions!

We will be hosting a live twitter spaces in a couple of weeks to discuss this, stay on the look out for more info!

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Hi @LeCryptoMath,

The links are not working and I couldn’t find them on the /zips repository - can you help me fix it?

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Hi!
I’m sharing the links here:

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Thanks for the links! Are the ZIP drafts now in a state where they could actually be presented as draft PRs to the GitHub - zcash/zips: Zcash Improvement Proposals repository?

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(Speaking as a ZIP Editor.)

Ditto! These look great!

They appear to be. I would strongly encourage filing them as a PR, so that GitHub’s comment/suggestion/review features can be used and so that changes can be tracked.

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this is a great point! We will make sure to do this in the next few days.

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Yes please, this would be great to track questions/reviews/suggestions/what has been discussed and what not

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Dear all, after some time, please find our monthly update (sorry that we skipped one, between time off and initial development, there was not a lot to update on).

The last two months we have done important progress, ironing out many details of the design of the protocol and the circuit. Specifically,

  1. We have created a pull request with the draft versions of

  2. We have been advancing at a good pace with the implementation of the protocol

    • The transfer protocol changes are pretty advanced - see repo
    • The client implementation (RPC) for the ZSA functionality is also advancing well - see repo’s main branch
    • We are also getting started with the issuance implementation, having already implemented the issuance key structure - see this pull request
  3. We are advancing with the ZIP for the fee mechanism, though we do not feel like we are ready to share the draft. More on this soon!

  4. We are getting ready to present our work and progress at Zcon3!! We will have one session with concrete design overview, updates and (hopefully) a demo. And we will also host an interactive discussion on the future applications and protocol design for the Zcash blockchain (i.e.: towards real programmability). Do not miss it out.

We are hear to answer any questions!
Thank you all,
The QEDIT team.

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Thankyou, this is awesome! We made a start on editing in the ZIP sync meeting on Wednesday. Looking forward to seeing the QEDIT team at Zcon!

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Dear Zcash Community,

We are very excited to share with you that we are advancing well with the implementations of the Transfer, Issuance and Burn mechanisms. This update is divided in two parts: first, a detailed update on the project progress; second a request to change the project milestone structure.

Updates

Last month we had very productive conversations at Zcon3, including a talk we gave on the details of the ZSA project, a workshop we facilitated on the future of Zcash applications, and a panel discussion I participated on the future of Zcash. We welcome any feedback and questions on any of these.

In terms of the final ZIP, the Fees Mechanism ZIP

Regarding the implementations,

  • The transfer mechanism is mostly done (yay!), and we are writing tests, many tests. We are also currently working on the circuit updates, which ended up making the circuit a bit larger than expected, so we are also looking at how to optimize the floor plan of the circuit (see Str4d’s talk at Zcon3). The main overheads were that in order to compute the note commitment of typed assets, we needed to add an extra round of the sinsemilla hash window, and also the fact that we ended up having more branching in the circuit, due to the different cases that need to be handled (mainly the differences between ZEC and non-ZEC notes, real and split / dummy notes). Good news is that we have some ideas for how to optimize the circuit.
  • In terms of the issuance protocol, we are also done in the Orchard repo (woop!), and we are also writing many tests. There is work to be done at the client layer (especially given the complexity of the Zcashd client), in order to ensure that the issuers can easily program their concrete issuance application (NFTs, Multi-issuance, delayed, etc…). Given that the issuance is new to the core protocol, there are some consensus changes to implement.
  • We are working on the burn mechanism, for which we have decided to not implement any specific burning method, and instead leave it up to the bridge operators to decide how to transmit the necessary information between the user of the token and the bridge operator.

Milestones Refining

As we approach the end of the implementation milestones, we are preparing for the next part of the project, the review and deployment, and we would like to refine and reorganize some of the milestones in a formal way. This will allow QEDIT to define our timeline in a more concrete manner, especially as we look towards future projects. Currently, there is a single project and grant for everything from design, implementation, code review, testnet deployment to mainnet deployment.

Practically, we have worked on these milestones in a different order, so we would like to propose that we divide the project (all ZSA milestones, as defined here) into two different phases:

  1. For the first phase of the project, we include all the design and implementation milestones (number 1, 2, 3, 4, 5, 6, 7 and 8). Furthermore, we would like to divide milestone 3 (Transfer Functionality Implementation) into two different milestones, with two different PRs to the Orchard repository, making it a cleaner deliverable:
    1. Milestone 3a. Transfer Protocol Implementation: will include every aspect of the implementation pertaining to the actual protocol, and would comprise 60% of the budget allocated to milestone 3. The deliverable for this milestone is a PR to the main zcash/orchard repo.
    2. Milestone 3b. Transfer Proof Circuit Implementation: will include every aspect of the circuit writing, as this entails optimization work, and would comprise 40% of the budget allocated to milestone 3. The deliverable for this milestone is a PR to the main zcash/orchard repo.
  2. The second part of the project, preparing for deployment, we include the review, testnet and mainnet deployment milestones, which have a less specific delivery time and require on-going work. This would include milestones number 9 and 10 (as seen in the image above), expanding on the last milestone to include fixing any vulnerabilities or bugs found in any of the processes.

In terms of the budget, we would maintain the same budget as per the original project, but dividing the payment into two different sets, as per budget outlined in the original proposal.

We truly believe that this division should be adopted by all teams applying for grants to implement on the core layer of the Zcash ecosystem.

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Thank you for providing the update on the implementation milestones and the adjusted timelines for the deliverables. And thanks for communicating the breakdown of Milestone 3 into two different milestones.

Please connect with @decentralistdan for help with updating the milestone setup on the zcashgrants.org platform.

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