CIP-68

Overview

Meaning and scope

CIP-68 is Cardano’s datum metadata standard for programmable native assets whose metadata can be read and updated through on-chain outputs. Unlike transaction-metadata approaches, the datum can be inspected by Plutus validators and updated under rules enforced by a smart contract. Token labels help wallets and indexers classify the reference and user assets, but correct interpretation requires following the standard’s encoding.

Mechanism and operation

CIP-68 defines a Cardano metadata pattern using paired native assets and an output carrying an inline datum. A reference token identifies and controls the metadata state, while a user token represents the asset held or transferred by users. Applications should verify policy IDs, token labels, the reference NFT, datum schema, and controlling script before displaying metadata. Mutability must be communicated clearly, because an image or property may change after purchase if the script permits an authorized update. Conformance to CIP-68 requires more than matching a field name or example. Teams adopting CIP-68 should track errata, compatibility changes, and the deployed software versions that enforce it.

Practical payment example

A Cardano token indexer resolves a user token to its corresponding reference NFT and datum. It checks the shared policy ID and labeled asset names before displaying metadata that can be governed by the reference output.

Operational checks

The metadata lookup should derive the reference NFT from the user token using the standard label rules, verify the policy ID and inspect the datum at the reference output. Review whether scripts allow metadata updates. An indexer must not infer an immutable collectible merely because the currently displayed datum is valid. CIP-68 should be implemented against an exact document revision, status, and activation context.

Distinctions and limits

CIP-68 concerns the representation and retrieval of token metadata; it does not itself guarantee payment finality, stable market value or immutable properties. An issuer’s controlling script may permit updates, so consumers must examine the metadata governance rules relevant to the asset. CIP-68 enables programmable, on-chain-readable Cardano metadata through linked reference and user tokens governed by script rules.

Related reading

Related definitions: smart contract.