HackMD
  • Prime
    Prime  Full-text search on all paid plans
    Search anywhere and reach everything in a Workspace with Prime plan.
    Got it
      • Create new note
      • Create a note from template
    • Prime  Full-text search on all paid plans
      Prime  Full-text search on all paid plans
      Search anywhere and reach everything in a Workspace with Prime plan.
      Got it
      • Options
      • Versions and GitHub Sync
      • Transfer ownership
      • Delete this note
      • Template
      • Save as template
      • Insert from template
      • Export
      • Dropbox
      • Google Drive
      • Gist
      • Import
      • Dropbox
      • Google Drive
      • Gist
      • Clipboard
      • Download
      • Markdown
      • HTML
      • Raw HTML
      • Sharing Link copied
      • /edit
      • View mode
        • Edit mode
        • View mode
        • Book mode
        • Slide mode
        Edit mode View mode Book mode Slide mode
      • Note Permission
      • Read
        • Owners
        • Signed-in users
        • Everyone
        Owners Signed-in users Everyone
      • Write
        • Owners
        • Signed-in users
        • Everyone
        Owners Signed-in users Everyone
      • More (Comment, Invitee)
      • Publishing
        Everyone on the web can find and read all notes of this public team.
        After the note is published, everyone on the web can find and read this note.
        See all published notes on profile page.
      • Commenting Enable
        Disabled Forbidden Owners Signed-in users Everyone
      • Permission
        • Forbidden
        • Owners
        • Signed-in users
        • Everyone
      • Invitee
      • No invitee
    Menu Sharing Create Help
    Create Create new note Create a note from template
    Menu
    Options
    Versions and GitHub Sync Transfer ownership Delete this note
    Export
    Dropbox Google Drive Gist
    Import
    Dropbox Google Drive Gist Clipboard
    Download
    Markdown HTML Raw HTML
    Back
    Sharing
    Sharing Link copied
    /edit
    View mode
    • Edit mode
    • View mode
    • Book mode
    • Slide mode
    Edit mode View mode Book mode Slide mode
    Note Permission
    Read
    Owners
    • Owners
    • Signed-in users
    • Everyone
    Owners Signed-in users Everyone
    Write
    Owners
    • Owners
    • Signed-in users
    • Everyone
    Owners Signed-in users Everyone
    More (Comment, Invitee)
    Publishing
    Everyone on the web can find and read all notes of this public team.
    After the note is published, everyone on the web can find and read this note.
    See all published notes on profile page.
    More (Comment, Invitee)
    Commenting Enable
    Disabled Forbidden Owners Signed-in users Everyone
    Permission
    Owners
    • Forbidden
    • Owners
    • Signed-in users
    • Everyone
    Invitee
    No invitee
       owned this note    owned this note      
    Published Linked with GitHub
    Like BookmarkBookmarked
    Subscribed
    • Any changes
      Be notified of any changes
    • Mention me
      Be notified of mention me
    • Unsubscribe
    Subscribe
    # Zcash Shielded Assets - Issuance The design concerns about ZSAs can be roughly split into three areas: - How to issue (and redeem / burn) assets. - How to transact with them. - How to handle fees. This document covers the first area: what is necessary for defining, issuing, and removing from issuance (redeeming or burning) non-ZEC assets. The goal of this document is to document: - the requirements that various use cases place on issuance functionality; and - the functionality that various issuance designs provide, to enable us to find the intersection of these two groups. ## Definitions - "Asset ID": the globally-unique identifier for a specific asset within the Zcash block chain. - "Native asset": an asset natively defined within the Zcash block chain. - "Guest asset": an asset defined off-chain, that can be locked up there and represented equivalently within the Zcash block chain. - "Issuance": addition of some amount of a specific asset to general circulation within the Zcash block chain. - "Redemption": removal of some amount of a specific asset from general circulation within the Zcash block chain. - "Governing body": the entity or entities that control a specific asset, and are permissioned to perform issuance, redemption, or other similar actions. - "Rotation": altering the effective membership of the governing body for a specific asset. This might not alter the actual membership (e.g. a member rotating their key). ## Potential use cases ### Generating custom native currency assets. TODO: Expand this. Possible requirements: - Asset issuance and redemption is public. ### Generating custom native non-currency tokens. TODO: Expand this (and how it differs in use-case from "custom native currency asset"). Possible requirements: - Asset issuance and redemption is public. ### Enabling existing off-chain assets to be wrapped as guest assets. > This section needs expanding. In particular, we need feedback from existing bridgemakers to elucidate what they actually require. > [name=str4d] TODO: Expand on the ways in which people do cross-chain asset movement. Requirements: - Asset issuance and redemption is public. - This is necessary to ensure that the amount of the guest asset within the Zcash block chain matches the amount of the guest asset locked up off-chain. Possible requirements: - Asset issuance and redemption is public. - Support for some kind of multisig. - [UNCONFIRMED] Support for FROST-like multisig. - [UNCONFIRMED] Support for Bitcoin-style multisig. - [UNCONFIRMED] Support for existing BTC/ETH sigs/curves/ideally keys. ### tBTC > A dynamic set of keys with the power to issue a single asset ID would be ideal for our designs. > [name=Matt Luongo] Requirements: - A signature scheme that's verifiable on Ethereum. So secp256k1 curve, but ECDSA or BLS works. - I don't know of any Schnorr implementation that's efficient on the EVM [name=Matt Luongo] - Multiple governing bodies for a specific asset ID. - A way to verify redemptions. In particular, need to know: - X amount of asset ID was burned to redeem, - committing to Y Ethereum account. ## Possible issuance designs We assume for the moment that all designs are implemented as a TZE. This would potentially enable some degree of custom issuance logic; we'd split the logic into "common to all ZSAs" (part of the TZE logic) and "per-ZSA" (provided in the TZE witness for each issuance or redemption transaction). TODO: Rework how this is outlined; TZEs are conceptually just the implementation mechanism, but they do place some constraints on how issuance transactions actually work (mostly due to the UTXO model). ### Single-key == asset An asset ID is derived from a single public key that controls the asset. Issuance and redemption transactions are authorized by a signature from this public key. Full nodes would need to maintain: - A list of currently-issued assets, and the amount of each that has been issued. Assets that have never been issued or never been redeemed could be elided. Notes: - This is the absolute simplest approach to design, specify, and implement. - It is compatible with threshold multisignature schemes like FROST (where the multisignature public key is indistinguishable from a single key). - It is _not_ compatible with Bitcoin-style multi-key multisignatures (where all keys involved in a signature are revealed). - It does not support key rotation. Changing the public key changes the asset ID. ### Single-key registered to asset When an asset ID is first "registered" (e.g. on first use), it can specify a single public key that controls the asset. Full nodes would need to maintain an indefinitely-growing list of registered assets, - It is compatible with threshold multisignature schemes like FROST. - It could be extended to support key rotation, by having a "rotation" action that is authorized by the previous key. ### Multi-key == asset Equivalent to "single-key == asset", but instead the asset ID is derived from a concatenated list of public keys. - It could be extended to a threshold scheme by also including the required threshold in the asset ID derivation. ### Multi-key registered to asset Equivalent to "single-key registered to asset", but instead registering a list of public keys. - It could be extended to a threshold scheme by also including the required threshold in the asset ID derivation. - The threshold could potentially be updateable. Key rotation could be defined with a potentially-different authorization mechanism for individual keys: - Issuance or redemption requires signatures from all keys on the list (or a subset of them if a threshold is specified). - but rotating an individual key ### scriptpubkey registered to an asset: We use a TZE to store {assetID: scriptpubkey} supporting two operations three operations: 1) register: creates a new assetID,scriptpubKey pair (either a random asset ID, or the hash of the scruptpubKey) 2) mint: issues x units of an asset with assID IFF the script pubkey is satisfied 3) update: for assetID ID, change the scriptpubkey from X to Y IFF x is satisfied. ### "Smart contract" registered to asset We likely won't do this, but including it here as a design alternative. TODO: Describe.

    Import from clipboard

    Advanced permission required

    Your current role can only read. Ask the system administrator to acquire write and comment permission.

    This team is disabled

    Sorry, this team is disabled. You can't edit this note.

    This note is locked

    Sorry, only owner can edit this note.

    Reach the limit

    Sorry, you've reached the max length this note can be.
    Please reduce the content or divide it to more notes, thank you!

    Import from Gist

    Import from Snippet

    or

    Export to Snippet

    Are you sure?

    Do you really want to delete this note?
    All users will lost their connection.

    Create a note from template

    Create a note from template

    Oops...
    This template is not available.


    Upgrade

    All
    • All
    • Team
    No template found.

    Create custom template


    Upgrade

    Delete template

    Do you really want to delete this template?

    This page need refresh

    You have an incompatible client version.
    Refresh to update.
    New version available!
    See releases notes here
    Refresh to enjoy new features.
    Your user state has changed.
    Refresh to load new user state.

    Sign in

    Forgot password

    or

    By clicking below, you agree to our terms of service.

    Sign in via Facebook Sign in via Twitter Sign in via GitHub Sign in via Dropbox Sign in via Google

    New to HackMD? Sign up

    Help

    • English
    • 中文
    • Français
    • Deutsch
    • 日本語
    • Español
    • Català
    • Ελληνικά
    • Português
    • italiano
    • Türkçe
    • Русский
    • Nederlands
    • hrvatski jezik
    • język polski
    • Українська
    • हिन्दी
    • svenska
    • Esperanto
    • dansk

    Documents

    Tutorials

    Book Mode Tutorial

    Slide Mode Tutorial

    YAML Metadata

    Contacts

    Facebook

    Twitter

    Feedback

    Send us email

    Resources

    Releases

    Pricing

    Blog

    Policy

    Terms

    Privacy

    Cheatsheet

    Syntax Example Reference
    # Header Header 基本排版
    - Unordered List
    • Unordered List
    1. Ordered List
    1. Ordered List
    - [ ] Todo List
    • Todo List
    > Blockquote
    Blockquote
    **Bold font** Bold font
    *Italics font* Italics font
    ~~Strikethrough~~ Strikethrough
    19^th^ 19th
    H~2~O H2O
    ++Inserted text++ Inserted text
    ==Marked text== Marked text
    [link text](https:// "title") Link
    ![image alt](https:// "title") Image
    `Code` Code 在筆記中貼入程式碼
    ```javascript
    var i = 0;
    ```
    var i = 0;
    :smile: :smile: Emoji list
    {%youtube youtube_id %} Externals
    $L^aT_eX$ LaTeX
    :::info
    This is a alert area.
    :::

    This is a alert area.

    Versions

    Versions and GitHub Sync

    Sign in to link this note to GitHub Learn more
    This note is not linked with GitHub Learn more
     
    Add badge Pull Push GitHub Link Settings
    Upgrade now

    Version named by    

    More Less
    • Edit
    • Delete

    Note content is identical to the latest version.
    Compare with
      Choose a version
      No search result
      Version not found

    Feedback

    Submission failed, please try again

    Thanks for your support.

    On a scale of 0-10, how likely is it that you would recommend HackMD to your friends, family or business associates?

    Please give us some advice and help us improve HackMD.

     

    Thanks for your feedback

    Remove version name

    Do you want to remove this version name and description?

    Transfer ownership

    Transfer to
      Warning: is a public team. If you transfer note to this team, everyone on the web can find and read this note.

        Link with GitHub

        Please authorize HackMD on GitHub

        Please sign in to GitHub and install the HackMD app on your GitHub repo. Learn more

         Sign in to GitHub

        HackMD links with GitHub through a GitHub App. You can choose which repo to install our App.

        Push the note to GitHub Push to GitHub Pull a file from GitHub

          Authorize again
         

        Choose which file to push to

        Select repo
        Refresh Authorize more repos
        Select branch
        Select file
        Select branch
        Choose version(s) to push
        • Save a new version and push
        • Choose from existing versions
        Available push count

        Upgrade

        Pull from GitHub

         
        File from GitHub
        File from HackMD

        GitHub Link Settings

        File linked

        Linked by
        File path
        Last synced branch
        Available push count

        Upgrade

        Danger Zone

        Unlink
        You will no longer receive notification when GitHub file changes after unlink.

        Syncing

        Push failed

        Push successfully