MVR Provenance Metadata Spec

This document describes how provenance metadata is stored and retrieved in the Move Registry (MVR), particularly for validating smart contract deployments with .intoto.jsonl files.

🧱 Metadata Storage Convention

🔑 Metadata Key Conventions

• prov_tx: The transaction digest (hex string) of the original on-chain deployment. Used for verifying that the published bytecode matches.
• prov_jsonl_0, prov_jsonl_1, ...: Chunks of the .intoto.jsonl file, encoded in base64 and split by byte-length.
• prov_params_0, prov_params_1, ...: Chunks of the base64-encoded JSON that includes extracted function names and parameters.

📏 Chunking Logic

Chunks are split based on byte length, not character count, due to on-chain field length constraints. In testing, the maximum reliable chunk size was 16380 bytes per string.

The following function is used to split base64 data:

const splitBase64ByByteLength = (base64: string, maxBytes: number): string[] => {
  const encoder = new TextEncoder();
  const bytes = encoder.encode(base64);
  const chunks: string[] = [];

  for (let i = 0; i < bytes.length; i += maxBytes) {
    const slice = bytes.slice(i, i + maxBytes);
    chunks.push(new TextDecoder().decode(slice));
  }

  return chunks;
};

💾 Storage Targets

• App-level metadata is stored via move_registry::set_metadata, using the application capability (AppCap).
• Package-level metadata is stored via package_info::set_metadata, using the PackageInfo object.

🧪 Retrieving and Verifying Metadata

You can retrieve metadata from MVR’s public API:

https://mainnet.mvr.mystenlabs.com/v1/names/[your_app_name]

The following logic reconstructs the full .intoto.jsonl and function param JSON:

import { fromBase64 } from '@mysten/sui/utils';

const joinChunks = (prefix: string, metadata: Record<string, string>) => {
  const chunks = Object.entries(metadata)
    .filter(([key]) => key.startsWith(prefix))
    .sort(([a], [b]) => {
      const aIndex = parseInt(a.split('_')[1], 10);
      const bIndex = parseInt(b.split('_')[1], 10);
      return aIndex - bIndex;
    })
    .map(([, value]) => value);

  return chunks.length > 0 ? chunks.join('') : undefined;
};

const getMvrData = async (name: string) => {
  const response = await fetch(`https://mainnet.mvr.mystenlabs.com/v1/names/${name}`);
  const json = await response.json();
  const metadata = json.package_info.metadata || {};

  return {
    digest: metadata.prov_tx,
    provenance: joinChunks('prov_jsonl_', metadata),
    params: JSON.parse(
      new TextDecoder().decode(fromBase64(joinChunks('prov_params_', metadata) ?? '')),
    ),
  };
};

🎯 Usage

• prov_tx: Used to retrieve the on-chain package via transaction digest and compare bytecode.
• prov_jsonl_*: Used to reconstruct .intoto.jsonl and verify Sigstore provenance.
• prov_params_*: Used by clients to reconstruct function parameter metadata (e.g., for GUI display).

📌 Notes

• All metadata is stored using set_metadata functions.
• Chunks are sorted by index suffix _0, _1, ...
• Developers verifying provenance should always compare .intoto.jsonl content against the current package hash extracted from prov_tx.