Aries OCA Bundles

This GitHub repository is for hosting published Overlays Capture Architecture (OCA) Bundles to be used by Hyperledger Aries agents (issuers, holders and verifiers). The repository includes a lightweight governance process for ensuring those contributing to the repository are the "authority" over the OCA Bundle they are submitting/updating, and that what they are submitting is, in fact, an OCA Bundle for a published AnonCreds Schema and/or Credential Definition.

The OCA Bundles should follow the rules for OCA for Aries OCA Bundles, including the OCA for Aries Style Guide. Each OCA Bundle must be accompanied by some metadata about the credential, such as on what ledger the credential schema and definition (CredDef) reside, and may be accompanied by the full OCA Source data--Excel and JSON files. We have some tools in the repo for converting OCA Source to the Bundle to make it easier for contributors.

Currently, the repository assumes that the OCA Bundles are for Hyperledger AnonCreds Verifiable Credentials. We expect that other formats, such as W3C Verifiable Credentials Data Model Standard JSON-LD credentials will eventually also be supported.

Previewing And Designing OCA Bundles

When it comes to creating an OCA Bundle previewing the branding can be done with the OCA Explorer

What is OCA Explorer

Overlays Capture Architecture (OCA) allows issuers to control the look of a credentials in a users wallet. In addition, OCA makes supporting multiple languages such as French and English easy.

Using OCA Explorer

To design and preview an OCA Bundle, head over to the OCA Explorer and either select an existing bundle in the repository or upload one of your own.

Once you have selected or uploaded an OCA Bundle, a preview will display. If configured in the bundler there may be the option to choose from a variety of available languages using radio buttons based on the multilingual overlay.

The remaining fields displayed are derived from the branding overlay, which can be customized according to your preferences. You can easily fill in these fields and download the branding overlay by clicking on the DOWNLOAD BRANDING OVERLAY button.

Take a look at the screenshot below for an idea of what the branding customization interface looks like:

Don't hesitate to experiment and create an OCA Bundle that best suits your needs!

Locations of OCA Bundles

OCA Bundles in this repository are found in the OCABundles folder in this repository. The folder structure within OCABundles is as follows with OCABundle JSON files in the <Credential> and <Schema> folders.

OCABundles
 ┣ credentials
 ┃ ┣ <Issuer>
 ┃ ┃ ┣ <Credential>
 ┃ ┃ ┗ <Credential>
 ┃ ┣ <Issuer>
 ┃ ┃ ┣ <Credential>
 ┃ ┃ ┗ <Credential>
 ┗ schema
 ┃ ┣ <Publisher>
 ┃ ┃ ┣ <Schema>
 ┃ ┃ ┗ <Schema>
 ┃ ┗ <Publisher>
 ┃ ┃ ┣ <Schema>
 ┃ ┃ ┗ <Schema>

Contributing an OCA Bundle

To contribute an OCA Bundle, create a pull request that adds the necessary files for the Aries for OCA:

• In the OCABundles schema or credentials folder, if needed, create a new <Issuer> or <Publisher>. Those folders are for organizing the credentials and the folder naming is up to the submitter.
• Within that folder, create another folder named for the schema or credential definition being added.
• Within that folder, add the following files, as appropriate:
  • README.md: MUST be present and MUST contain the information outlined below in the README File Content section of this document.
  • OCABundle.json: MUST be present and MUST contain the OCA Bundle for the schema or credential definition.
  • <OCASourceExcel>.xlsx: (optional) An Excel OCA Source file for the OCA Bundle.
  • branding.json: (optional) A JSON file containing the source content for the OCA for Aries Branding overlay.
  • testdata.csv: (optional) A CSV file containing one or more sample data records.
  • Other files: (optional) Other files related to the OCA Bundle, such as the images used in the branding.json file.

The pull request will be reviewed according to the lightweight governance process and merged (or not) into the repository.

README File Content

The README.md file for the OCA Bundle MUST be present and MUST include begin with the information shown and described below. The formatting requirements are in place because the file is processed by a script that generates a list of all of the identifiers (schemaIds and credDefIds) and the OCA Bundles to which they are associated with.

# <TITLE>

<DESCRIPTION>

- Publishing Organization: <ORGANIZATION>
- Primary Contact Email Address: <CONTACT EMAIL ADDRESS>

## Identifiers

| Identifier                                 | Location  | URL         |
| ------------------------------------------ | --------- | ----------- |
| <SCHEMA ID or CRED DEF ID>                 | <LEDGER>  | <URL>       |

## Authorization

The following are the GitHub IDs of those authorized to make substantive updates to the OCA Bundle.

| OCA Bundle Contributors | GitHub ID   | Email Address            |
| ----------------------- | ----------- | ------------------------ |
| <NAME>                  | <GITHUB ID> | <EMAIL ADDRESS>          |

Everything not in <>s must be exactly as specified above (with one exception--see below). Everything in <>s MUST be populated as described below.

The two markdown tables MAY have multiple lines. Multiple lines in the Identifiers table indicates that the same OCA Bundle is used for each of the objects identified in the first column. Multiple lines in the Authorization table is recommended so that multiple members of the submitters team may update the OCA Bundle.

• <TITLE> MUST be the name of the credential type. No other line in the file can have a single # prefix.
• <DESCRIPTION> is extracted for display by tools for processing this repository (such as the OCA Explorer) and should describe the type of credential to which the OCA Bundle applies.
• <ORGANIZATION> is extracted for display by tools for processing this repository (such as the OCA Explorer) and is the name of the organization that submitted the OCA Bundle.
• <CONTACT EMAIL ADDRESS> is an email address for the primary contact for the OCA Bundle. The address may for a person, or better, a group contact withing the <ORGANIZATION>.
• <SCHEMA ID or CRED DEF ID> are identifiers for objects to which the OCA Bundles applies. There can be multiple lines in the table, each with a different identifier.
• <LEDGER> is optional. It identifies the ledger on which the object identified by the object resides. It should be in the form [:] as defined in the did-indy specification for namespace -- e.g., candy:dev or sovrin. The value is useful when the <SCHEMA ID or CRED DEF ID> is unqualified (such as with legacy Indy identifiers) such that the precise location of the object is not known.
• <URL> is optional and is a plain (non-Markdown) link to a ledger browser instance of the object, such as to a transaction on https://indyscan.io or https://candyscan.idlab.org/
• `' is the name of a person authorized to update the OCA Bundle and related data. There may be multiple rows in the markdown table to name multiple people.
• <GITHUB ID> is the GitHub ID of the named person.
• <EMAIL ADDRESS> is the email address of the named person

The <CONTACT EMAIL ADDRESS> and the Authorization table are to ensure that once the OCA Bundle is submitted, there are contacts available to answer questions about, and to submit updates to, the OCA Bundle.

The contents of the Authorization section (following the ## Authorization line) may be replaced with the following to avoid repeating the same contents in every OCA Bundle README.md file:

The Authorization table for this OCA Bundle is in [this file](<path-to-another-OCABundle-folder/README.md).

Agent Processing

The following are the steps for processing the OCA Bundle by an Aries Holder or Verifier.

An Aries holder (wallet) or verifier agent MUST be pre-configured with the URL (<URL> in the following) for accessing raw files in the main branch of the OCABundles folder in this repository, e.g. https://raw.githubusercontent.com/bcgov/aries-oca-bundles/main.

On receipt of an AnonCreds Credential Definition ID (credDefid), the Aries agent SHOULD do the following:

• Load the JSON file <URL>/ocabundles.json.
  • This may be done at Aries wallet/agent initialization time and the contents cached. The wallet/agent may reload the file from time to time to get updates to the contents.
• Scan the list of identifiers for the credDefId in the loaded JSON data structure.
  • If found, use the corresponding path item value to load the OCA Bundle for the credential at (<URL>/<path>).
• Scan the list of identifiers for the schemaId referenced in the Credential Definition in the loaded JSON data structure.
  • If found, use the corresponding path item value to load the OCA Bundle for the credential at (<URL>/<path>).
• If not found, proceed without an OCA Bundle for the credential.

The wallet/agent may want to cache a loaded OCA Bundle.

Processing Notes

• A given Aries agent MAY want to pre-load OCA Bundles for Schemas or Credential Definitions all of the identifiers in the ocabundles.json file. From time-to-time, such agents may want to reload the Bundles in case they have been updated in the repository.

Creating the OCA Bundle JSON

See the instructions for creating an OCA Bundle JSON file from Excel and JSON source in the file OCABundleCreation.md in the root of this repository.