DID NFT Metadata Ownership

2 min readOct 10, 2021

Using IPLD and Cosmos

There is no such thing as a NFT Bridge

Reasons are:

  • Unique to a holder in 3 variables: denomination, id and metadata uri
  • The metadata might be offchain, ie allows forgery
  • Holder does not have cross chain accounts, ie complex UI / UX

Enter Ancon Protocol — DID NFT Metadata Ownership


Previously migrated / created onchain metadata in Ancon

How it works

  1. Alice changes metadata ownership in Ancon, DAG block gets replicated in IPFS, with status unconfirmed.
  2. Alice signs EIP1812 claim, issuing to Bob, token ownership and updated metadata ownership. It is registered onchain.
  3. Alice/Bob or Keeper job creates proof offchain.
  4. Verifier on the same chain as registry, verifies and applies safeTransferFrom, with a data payload which is ABI packed.
  5. Token receives transfer message and also updates token uri.
  6. Ancon and IPFS are eventually updated with cid token ownership as verified.

In this first release, we are focusing EVM-to-EVM use cases. We’ll work later on Sidetree registry for any-to-any. We’d like to get help from the community to get Verifiers implemented in other chains, next on our roadmap is Flow..

Use cases

With this once is implemented and online, you could:

  • Cross chain mint / distribution
  • 2ndary market in any chain supported with DIDs
  • Dynamic NFTs, using IPNS / ENS
  • Universal Royalty features


We also added Graphsync support to Ancon Protocol

— IFESA, Rogelio Morrell




Industrias de Firmas Electrónicas, S.A. (IFESA) es la primera empresa panameña dedicada a tecnologías basadas en algoritmos criptográficos, firmas electrónicas,