DDO Specification

Specification of decentralized identifiers for assets in Ocean Protocol using the DDO standard.

DDO Schema - High Level

The below diagram shows the high-level DDO schema depicting the content of each data structure and the relations between them.

Please note that some data structures apply only on certain types of services or assets.

Required Attributes

A DDO in Ocean has these required attributes:

Full Enhanced DDO Example
{
  "@context": ["https://w3id.org/did/v1"],
  "id": "did:op:ACce67694eD2848dd683c651Dab7Af823b7dd123",
  "version": "4.1.0",
  "chainId": 1,
  "nftAddress": "0x123",
  "metadata": {
    "created": "2020-11-15T12:27:48Z",
    "updated": "2021-05-17T21:58:02Z",
    "description": "Sample description",
    "name": "Sample asset",
    "type": "dataset",
    "author": "OPF",
    "license": "https://market.oceanprotocol.com/terms"
  },
  "services": [
    {
      "id": "1",
      "type": "access",
      "files": "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",
      "name": "Download service",
      "description": "Download service",
      "datatokenAddress": "0x123",
      "serviceEndpoint": "https://myprovider.com",
      "timeout": 0,
      "consumerParameters": [
        {
          "name": "surname",
          "type": "text",
          "label": "Name",
          "required": true,
          "default": "NoName",
          "description": "Please fill your name"
        },
        {
          "name": "age",
          "type": "number",
          "label": "Age",
          "required": false,
          "default": 0,
          "description": "Please fill your age"
        }
      ]
    },
    {
      "id": "2",
      "type": "compute",
      "files": "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",
      "name": "Compute service",
      "description": "Compute service",
      "datatokenAddress": "0x124",
      "serviceEndpoint": "https://myprovider.com",
      "timeout": 3600,
      "compute": {
        "allowRawAlgorithm": false,
        "allowNetworkAccess": true,
        "publisherTrustedAlgorithmPublishers": ["0x234", "0x235"],
        "publisherTrustedAlgorithms": [
          {
            "did": "did:op:123",
            "filesChecksum": "100",
            "containerSectionChecksum": "200"
          },
          {
            "did": "did:op:124",
            "filesChecksum": "110",
            "containerSectionChecksum": "210"
          }
        ]
      }
    }
  ],
  "credentials": {
    "allow": [
      {
        "type": "address",
        "values": ["0x123", "0x456"]
      }
    ],
    "deny": [
      {
        "type": "address",
        "values": ["0x2222", "0x333"]
      }
    ]
  },

  "nft": {
    "address": "0x123",
    "name": "Ocean Protocol Asset",
    "symbol": "OCEAN-A",
    "owner": "0x0000000",
    "state": 0,
    "created": "2000-10-31T01:30:00",
    "tokenURI": "xxx"
  },

  "datatokens": [
    {
      "address": "0x000000",
      "name": "Datatoken 1",
      "symbol": "DT-1",
      "serviceId": "1"
    },
    {
      "address": "0x000001",
      "name": "Datatoken 2",
      "symbol": "DT-2",
      "serviceId": "2"
    }
  ],

  "event": {
    "tx": "0x8d127de58509be5dfac600792ad24cc9164921571d168bff2f123c7f1cb4b11c",
    "block": 12831214,
    "from": "0xAcca11dbeD4F863Bb3bC2336D3CE5BAC52aa1f83",
    "contract": "0x1a4b70d8c9DcA47cD6D0Fb3c52BB8634CA1C0Fdf",
    "datetime": "2000-10-31T01:30:00"
  },

  "purgatory": {
    "state": false
  },

  "stats": {
    "orders": 4
  }
}

Metadata

This object holds information describing the actual asset.

* Required

** Required for algorithms only

Metadata Example
{
  "metadata": {
    "created": "2020-11-15T12:27:48Z",
    "updated": "2021-05-17T21:58:02Z",
    "description": "Sample description",
    "name": "Sample asset",
    "type": "dataset",
    "author": "OPF",
    "license": "https://market.oceanprotocol.com/terms"
  }
}

Services

Services define the access for an asset, and each service is represented by its respective datatoken.

An asset should have at least one service to be actually accessible and can have as many services which make sense for a specific use case.

* Required

** Required for compute assets only

Files

The files field is returned as a string which holds the encrypted file URLs.

Files Example
{
  "files": "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"
}

Credentials

By default, a consumer can access a resource if they have 1 datatoken. Credentials allow the publisher to optionally specify more fine-grained permissions.

Consider a medical data use case, where only a credentialed EU researcher can legally access a given dataset. Ocean supports this as follows: a consumer can only access the resource if they have 1 datatoken and one of the specified "allow" credentials.

This is like going to an R-rated movie, where you can only get in if you show both your movie ticket (datatoken) and some identification showing you're old enough (credential).

Only credentials that can be proven are supported. This includes Ethereum public addresses and in the future W3C Verifiable Credentials and more.

Ocean also supports deny credentials: if a consumer has any of these credentials, they can not access the resource.

Here's an example object with both allow and deny entries:

Credentials Example
{
  "credentials": {
    "allow": [
      {
        "type": "address",
        "values": ["0x123", "0x456"]
      }
    ],
    "deny": [
      {
        "type": "address",
        "values": ["0x2222", "0x333"]
      }
    ]
  }
}

DDO Checksum

In order to ensure the integrity of the DDO, a checksum is computed for each DDO:

const checksum = sha256(JSON.stringify(ddo));

The checksum hash is used when publishing/updating metadata using the setMetaData function in the ERC721 contract, and is stored in the event generated by the ERC721 contract.

MetadataCreated and MetadataUpdated smart contract events
event MetadataCreated(
  address indexed createdBy,
  uint8 state,
  string decryptorUrl,
  bytes flags,
  bytes data,
  bytes metaDataHash,
  uint256 timestamp,
  uint256 blockNumber
);

event MetadataUpdated(
  address indexed updatedBy,
  uint8 state,
  string decryptorUrl,
  bytes flags,
  bytes data,
  bytes metaDataHash,
  uint256 timestamp,
  uint256 blockNumber
);

Aquarius should always verify the checksum after data is decrypted via a Provider API call.

State

Each asset has a state, which is held by the NFT contract. The possible states are:

States details:

  1. Active: Assets in the "Active" state are fully functional and available for discovery in Ocean Market, and other components. Users can search for, view, and interact with these assets. Ordering is allowed, which means users can place orders to purchase or access the asset's services.

  2. End-of-life: Assets in the "End-of-life" state remain discoverable but cannot be ordered. This state indicates that the assets are usually deprecated or outdated, and they are no longer actively promoted or maintained.

  3. Deprecated (by another asset): This state indicates that another asset has deprecated the current asset. Deprecated assets are not discoverable, and ordering is not allowed. Similar to the "End-of-life" state, deprecated assets are not listed under the owner's profile.

  4. Revoked by publisher: When an asset is revoked by its publisher, it means that the publisher has explicitly revoked access or ownership rights to the asset. Revoked assets are not discoverable, and ordering is not allowed.

  5. Ordering is temporarily disabled: Assets in this state are still discoverable, but ordering functionality is temporarily disabled. Users can view the asset and gather information, but they cannot place orders at that moment. However, these assets are still listed under the owner's profile.

  6. Asset unlisted: Assets in the "Asset unlisted" state are not discoverable. However, users can still place orders for these assets, making them accessible. Unlisted assets are listed under the owner's profile, allowing users to view and access them.

Aquarius Enhanced DDO Response

The following fields are added by Aquarius in its DDO response for convenience reasons, where an asset returned by Aquarius inherits the DDO fields stored on-chain.

These additional fields are never stored on-chain and are never taken into consideration when hashing the DDO.

NFT

The nft object contains information about the ERC721 NFT contract which represents the intellectual property of the publisher.

NFT Object Example
{
  "nft": {
    "address": "0x000000",
    "name": "Ocean Protocol Asset",
    "symbol": "OCEAN-A",
    "owner": "0x0000000",
    "state": 0,
    "created": "2000-10-31T01:30:00Z"
  }
}

Datatokens

The datatokens array contains information about the ERC20 datatokens attached to asset services.

Datatokens Array Example
{
  "datatokens": [
    {
      "address": "0x000000",
      "name": "Datatoken 1",
      "symbol": "DT-1",
      "serviceId": "1"
    },
    {
      "address": "0x000001",
      "name": "Datatoken 2",
      "symbol": "DT-2",
      "serviceId": "2"
    }
  ]
}

Event

The event section contains information about the last transaction that created or updated the DDO.

Event Example
{
  "event": {
    "tx": "0x8d127de58509be5dfac600792ad24cc9164921571d168bff2f123c7f1cb4b11c",
    "block": 12831214,
    "from": "0xAcca11dbeD4F863Bb3bC2336D3CE5BAC52aa1f83",
    "contract": "0x1a4b70d8c9DcA47cD6D0Fb3c52BB8634CA1C0Fdf",
    "datetime": "2000-10-31T01:30:00"
  }
}

Purgatory

Contains information about an asset's purgatory status defined in list-purgatory. Marketplace interfaces are encouraged to prevent certain user actions like adding liquidity on assets in purgatory.

Purgatory Example
{ 
    "purgatory": {
      "state": true,
      "reason": "Copyright violation" 
      } 

}
{
  "purgatory": {
    "state": false
  }
}

Statistics

The stats section contains different statistics fields.

Statistics Example
{
  "stats": {
    "orders": 4
  }
}

Compute to data

For algorithms and datasets that are used for compute to data, there are additional fields and objects within the DDO structure that you need to consider. These include:

  • compute attributes

  • publisherTrustedAlgorithms

  • consumerParameters

Details for each of these are explained on the Compute Options page.

DDO Schema - Detailed

The below diagram shows the detailed DDO schema depicting the content of each data structure and the relations between them.

Please note that some data structures apply only on certain types of services or assets.

Last updated

Logo

Copyright 2024 Ocean Protocol Foundation Ltd.