❓FAQs

1.How can I get started with the Guardian?

We recommend spending some time and reading carefully through the docs here: https://docs.hedera.com/guardian/getting-started/readme. You will find setup instructions, a glossary of important terms, demo walk throughs, and more.

2. How can I create policies?

You can use the UI policy editor or APIs to create a policy workflow. Examples are found in the guardian docs here: https://docs.hedera.com/guardian/getting-started/readme

3. Is there a demo to create a policy without importing it?

4. Can I see the Guardian product roadmap and the current backlog?

yes! just install the free chrome extension called zenhub https://www.zenhub.com/. When installed you will be able to see the "zenhub" tab in the Guardian's github repo

5. Where can I get notified of sprint updates and demos?

Every two weeks we publish sprint updates to this youtube playlist: https://youtube.com/playlist?list=PLnld0e1pwLhqb69cELqQrW87JFVIDfocL/

6. Where can I see the most recent changes made to the Guardian?

You can see the high level release notes here: https://github.com/hashgraph/guardian/releases. Also, you can find the full changelog at the bottom on the release notes to view for yourself via Github compare.

7. How do I request a policy or an issue to be worked on?

You can submit an issue in our Github or directly email us at info@envisionblockchain.com.

8. Whats the difference between iREC Policy and iREC Policy 2 in demo artifacts?

iREC Policy 2 is the up-to-date version of iREC Policy

9. How do I launch the IoT simulator in the reference implementation to generate demo MRV data?

You can visit : http://localhost:3000/mrv-sender/

10. how I can avoid the field name being "off by one" ?

Add an additional short name to the description in the schema configurator. If short name is not set then install field1...N.

11. How can I access the swagger docs for Guardian v2 ?

http://localhost:3000/api-docs/v1/ (note that this URL is only available for the docker build)

12. What is the difference between requestVcDocumentBlock and externalDataBlock to report data?

Both are for reporting data, both are producing VCs at the ‘exit.’ 1. requestVcDocumentBlock requires authorization, but the actual document is just json. 2. externalDataBlock does not require authorization, but the document must already be a VC and be correctly signed.

13. Why do I get the error INSUFFICENT_TX_FEE?

The fee in the transaction is too small and needs to be increased**.**

14. How are we linking topics to stored ipfs data after mongodb goes away? Is there somewhere I can read this?

MongoDB does not go away, we will keep the local DB for drafts etc. Hedera messages in topics are linked to the ‘published’ policies which are immutable stored in IPFS - messages contain CID of the file in IPFS.

15. Is MRV an existing data architecture used in I-REC or Carbon Offset standards?

A standard registry is an organization that establishes science-based standards for measuring, reporting, and verifying (MRV) ecological benefit claims and issues value in the form of credit for claims that meet the standard set. A standard registry also authorizes validation and verification bodies (VVBs) to collect and process claims based on the established standard. The creation of scientific-based standards for MRV is a rigorous discipline that requires independence from commercial influence in the pursuit of accurate accounting of benefit or emissions claims. In this case iREC is a standards registry, however oftentimes folks implement the iREC standard in a voluntary way and leverage iREC certification for sign off. Some markets, like Dubai, make it a compliance standard**.**

16. How Guardian uses IPFS for Verifiable Presentation (VP) storage?

When a policy is published a message is sent to the policy topic (on the policies page) where the policy (VP) and schemas are stored.

In the guardian a VP is a VP. It's just an object with schemas and dids inside of it.

17. How does Guardian Provenance works?

Here are the steps you should follow to get a VP from a token mint transaction.

Look for a token mint transaction on Ledger Works. For the transaction 00341948921649942497135549961 the link will be https://explore.lworks.io/testnet/transactions/0.0.34194892-1649942497-135549961 Transaction data will contain data similar to this:

TRANSACTION DETAILS 0.0.34194892@1649942497-135549961 (SUCCESS)
TRANSACTION TYPE Mint Token
TRANSACTION HASH 8ec781457fbd0ab6124eb04396cdcff153868f4f52b1836e42158fd3f23fc0139f1fd7b7ee18915124eab74d49c9d0ad
PAYER 0.0.34194892
MEMO 1649942508.776446488

Take the MEMO value (which is the Hedera message timestamp) and add it to the URL after the /messages/ to get a message from a Hedera Mirror Node. In our case it will be https://testnet.mirrornode.hedera.com/api/v1/topics/messages/1649942508.776446488 You will get a message content:

{
  "chunk_info": {
    "initial_transaction_id": {
      "account_id": "0.0.34194892",
      "nonce": 0,
      "scheduled": false,
      "transaction_valid_start": "1649942496.012855213"
    },
    "number": 1,
    "total": 1
  },
  "consensus_timestamp": "1649942508.776446488",
  "message": "eyJpZCI6IjEzNTZlMDNhLTk5NGEtNGU5ZC1iNTFmLWNlMGY4NzBmZDk1MiIsInN0YXR1cyI6IklTU1VFIiwidHlwZSI6IlZQLURvY3VtZW50IiwiYWN0aW9uIjoiY3JlYXRlLWNwLWRvY3VtZW50IiwiaXNzdWVyIjpudWxsLCJyZWxhdGlvbnNoaXBzIjpbIjE2NDk5NDI0OTYuMDEwMjExMDAwIl0sImNpZCI6ImJhZmtyZWlhNWkzYnJ1bWNpMzVzNzMzcTRndWEzNjNpaHhyaXNyNm56aWFmN2g3aGd4aHlhbmg2dnlhIiwidXJsIjoiaHR0cHM6Ly9pcGZzLmlvL2lwZnMvYmFma3JlaWE1aTNicnVtY2kzNXM3MzNxNGd1YTM2M2loeHJpc3I2bnppYWY3aDdoZ3hoeWFuaDZ2eWEifQ==",
  "payer_account_id": "0.0.34194892",
  "running_hash": "P0i9GNaL1qUoPQmNHOumV/3x8K4voPmOUNJOfXDJl9K89u/7Qa7GgqKR3kmaTcAF",
  "running_hash_version": 3,
  "sequence_number": 9,
  "topic_id": "0.0.34204397"
}

Take the message attribute value and parse it to a JSON representation: JSON.parse(atob(message)) // JSON.parse(atob(eyJpZCI6IjEzN.........WFuaDZ2eWEifQ==)) You will have a JSON similar to that one:

{
	"id": "1356e03a-994a-4e9d-b51f-ce0f870fd952",
	"status": "ISSUE",
	"type": "VP-Document",
	"action": "create-cp-document",
	"issuer": null,
	"relationships": [
		"1649942496.010211000"
	],
	"cid": "bafkreia5i3brumci35s733q4gua363ihxrisr6nziaf7h7hgxhyanh6vya",
	"url": "https://ipfs.io/ipfs/bafkreia5i3brumci35s733q4gua363ihxrisr6nziaf7h7hgxhyanh6vya"
}

Take the url attribute value and paste it to a browser: https://ipfs.io/ipfs/bafkreia5i3brumci35s733q4gua363ihxrisr6nziaf7h7hgxhyanh6vya You’ll have a VP of this token.

{
  "id": "db698146-38e2-48f6-8819-6f596647f970",
  "type": [
    "VerifiablePresentation"
  ],
  "@context": [
    "https://www.w3.org/2018/credentials/v1"
  ],
  "verifiableCredential": [
    {
      "id": "2f6ca45d-7f0d-405a-a011-b736db93e511",
      "type": [
        "VerifiableCredential"
      ],
      "issuer": "did:hedera:testnet:9ZJXR58X9XQUgwiuxQQiTUt5yY2vX2Tw5Uph4xXsnkfM;hedera:testnet:tid=0.0.34194893",
      "issuanceDate": "2022-04-14T13:21:28.918Z",
      "@context": [
        "https://www.w3.org/2018/credentials/v1"
      ],
      "credentialSubject": [
        {
          "field0": "did:hedera:testnet:F55HnMGMzS3TkuqBjLaUxcYvm86oGfTFViXELD4GNFAo;hedera:testnet:tid=0.0.34194893",
          "field1": "did:hedera:testnet:8jjgRqbr2YRYccxMrvhupyu543izSe8N1J6UHbgWkhiA;hedera:testnet:tid=0.0.34204397",
          "field2": {
            "type": "706bb8da-7f39-4518-85c3-b4b23a6ef28a",
            "@context": [
              "https://ipfs.io/ipfs/bafkreidcyabsha6frnfqie7bpa5o3yrb6cllglsxd4krjksvreg35ygluy"
            ]
          },
          "field3": {
            "type": "64c171a2-ac60-4972-b796-8596381c65a8",
            "@context": [
              "https://ipfs.io/ipfs/bafkreidcyabsha6frnfqie7bpa5o3yrb6cllglsxd4krjksvreg35ygluy"
            ]
          },
          "field6": "2022-04-07",
          "field7": 1,
          "field8": "2022-04-28",
          "field17": "nu81uxel",
          "field18": "0.0.34194895",
          "ref": "did:hedera:testnet:8jjgRqbr2YRYccxMrvhupyu543izSe8N1J6UHbgWkhiA;hedera:testnet:tid=0.0.34204397",
          "policyId": "62581e42a7303b7ff96a8012",
          "@context": [
            "https://ipfs.io/ipfs/bafkreidcyabsha6frnfqie7bpa5o3yrb6cllglsxd4krjksvreg35ygluy"
          ],
          "id": "6a730bc5-19e2-427d-b132-b9b49359ea20",
          "type": "143e109a-a089-48a1-8a7b-534bfaf79c4d&1.0.0"
        }
      ],
      "proof": {
        "type": "Ed25519Signature2018",
        "created": "2022-04-14T13:21:28Z",
        "verificationMethod": "did:hedera:testnet:9ZJXR58X9XQUgwiuxQQiTUt5yY2vX2Tw5Uph4xXsnkfM;hedera:testnet:tid=0.0.34194893#did-root-key",
        "proofPurpose": "assertionMethod",
        "jws": "eyJhbGciOiJFZERTQSIsImI2NCI6ZmFsc2UsImNyaXQiOlsiYjY0Il19..hw6O674MalfXIlD3RyOd1BLhvH_xBYIudK1UQ-cAvZxYYejdMjU2TYfjC-sUa7ZYcioZ_CfSBsMwI7WCO3hGAw"
      }
    },
    {
      "id": "c0c0d496-4f86-4ca9-94cc-80552d838168",
      "type": [
        "VerifiableCredential"
      ],
      "issuer": "did:hedera:testnet:9ZJXR58X9XQUgwiuxQQiTUt5yY2vX2Tw5Uph4xXsnkfM;hedera:testnet:tid=0.0.34194893",
      "issuanceDate": "2022-04-14T13:21:36.139Z",
      "@context": [
        "https://www.w3.org/2018/credentials/v1"
      ],
      "credentialSubject": [
        {
          "date": "2022-04-14T13:21:36.134Z",
          "tokenId": "0.0.34194898",
          "amount": "1",
          "@context": [
            "https://ipfs.io/ipfs/bafkreiaamzhmh3l5pn5nneib5yifb3gjwlotf6fr6vb65j7tfi4tefxcza"
          ],
          "type": "MintToken&1.0.0"
        }
      ],
      "proof": {
        "type": "Ed25519Signature2018",
        "created": "2022-04-14T13:21:36Z",
        "verificationMethod": "did:hedera:testnet:9ZJXR58X9XQUgwiuxQQiTUt5yY2vX2Tw5Uph4xXsnkfM;hedera:testnet:tid=0.0.34194893#did-root-key",
        "proofPurpose": "assertionMethod",
        "jws": "eyJhbGciOiJFZERTQSIsImI2NCI6ZmFsc2UsImNyaXQiOlsiYjY0Il19..3uhxt-NAuLaIGTDXlqkD92QOTUZOjJgHNjFwP6jrrGchFLwxuDDnhz5VzMMLv1k3_VkVLvIKx1V-E1aewSI5Bw"
      }
    }
  ],
  "proof": {
    "type": "Ed25519Signature2018",
    "created": "2022-04-14T13:21:36Z",
    "verificationMethod": "did:hedera:testnet:9ZJXR58X9XQUgwiuxQQiTUt5yY2vX2Tw5Uph4xXsnkfM;hedera:testnet:tid=0.0.34194893#did-root-key",
    "proofPurpose": "authentication",
    "challenge": "123",
    "jws": "eyJhbGciOiJFZERTQSIsImI2NCI6ZmFsc2UsImNyaXQiOlsiYjY0Il19..-yNpvBHaDnFk-T5OWY516WBsBnsE40E-4-z-d54BhwanRBN15D6VbKGUjRG4kkKhEp-7jh8WIO2VRsYY4-SOBQ"
  }
}

18. The VCs that are generated as part of the Guardian workflow, have you found any use cases where the status of the VC might change? For example, is there ever a time where a VC might be revoked or expires? If so, does the status get updated on the ledger?

there are many use-cases where the VCs and various other artefacts produced in the course of the policy functioning of the guardian might need to be revoked. One of the obvious examples of such situation is malfunctioning sensor generating invalid MRV data. But there are many others**.**

19. Is it possible to see a Guardian-minted token's value in hbar as well as its associated CO2e? If so, where does this information come from/how can we access it?

The value of the token in hbar (or USD) will be set by the market, and thus external to the token itself (so there is no way to see in the token what it is worth in $$). And what the token represents (CO2e etc) is determined by the policy under which it was minted. These tokens are the NFTs, and the metadata can include this data if the policy under which the tokens are minted has provisions for it.

20. What is the semantic of the DID in the message? Is it that the standard registry signs VCs etc with the corresponding private key?

DID is the the DID of the RA, i.e. is a globally unique reference linking to a DID document which is the identity - all VCs issued to or by an entity would then be ‘bound’ to this DID as per the ‘self-sovereign identity’ architecture.

21. How to identify data on Hedera after submitting data using sendToGuardianBlock?

When sending messages to the header, the Message Id and Topic Id are written to the database You can view them using the messageId and topicId fields

All messages in the topic can be viewed at the link https://explore.lworks.io/testnet/topics/0.0.47802089

for example**:**

https://explore.lworks.io/testnet/topics/{topicId}

Unfortunately, Ledger Works does not have a search by messageId, but messages can be obtained using mirrornode

for example https://testnet.mirrornode.hedera.com/api/v1/topics/messages/1659539040.128851003

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