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CIP-0010

Abstract​

Cardano transaction metadata forces metadata entries to namespace their content using an unsigned integer key. This specification is a registry of which use cases has allocated which number to avoid collisions.

Motivation: why is this CIP necessary?​

The top level of the transaction metadata CBOR object is a mapping of transaction_metadatum_label to the actual metadata where the transaction_metadatum_label represents an (ideally unique) key for a metadata use case. This allows enables the following:

1) Fast lookup for nodes to query all transactions containing metadata that uses a specific key 2) Allows a single transaction to include multiple metadata entries for different standards

Specification​

Terminology​

Transaction metadata refers to an optional CBOR object in every transaction since the start of the Shelley era. It is defined as the follow CDDL data structure

transaction_metadatum =
    { * transaction_metadatum => transaction_metadatum }
  / [ * transaction_metadatum ]
  / int
  / bytes .size (0..64)
  / text .size (0..64)

transaction_metadatum_label = uint

transaction_metadata =
  { * transaction_metadatum_label => transaction_metadatum }

Structure​

These are the reserved transaction_metadatum_label values

transaction_metadatum_labeldescription
0 - 15reserved*
65536 - 131071reserved - private use

For the registry itself, please see registry.json in the machine-readable format. Please open your pull request against this file.

  • It's best to avoid using 0 or any a similar number like 1 that other people are very likely to use. Prefer instead to generate a random number

Rationale: how does this CIP achieve its goals?​

Creating a registry for transaction_metadatum_label values has the following benefit:

1) It makes it easy for developers to know which transaction_metadatum_label to use to query their node if looking for transactions that use a standard 2) It makes it easy to avoid collisions with other standards that use transaction metadata

Path to Active​

Acceptance Criteria​

  • Consistent, long-term use by Cardano implementors of the metadata label registry by all applications requiring a universally acknowledged metadata label.
  • Consistent, long-term use in the CIP editing process: tagging, verifying, and merging new label requirements.

Implementation Plan​

  • Confirmed interest and cooperation in this metadata labelling standard and its registry.json convention by Cardano implementors: including NFT creators, data aggregators, and sidechains.

This CIP is licensed under CC-BY-4.0

CIP Information​

This null ./CIP-0010 created on 2020-10-31 has the status: Active.
This page was generated automatically from: cardano-foundation/CIPs.