Archived docs

This section contains instructions, and commentary relating to Orcfax solution versions and/or components which are no longer in operation. This information has been left as an educational resource and as a testament to the development journey of the Orcfax oracle solution.

v0

The v0 solution offered by Orcfax on Cardano mainnet was released in 2023 and utilized the Cardano Open Oracle Protocol (COOP) to format and publish information on-chain. The protocol constituted a set of technical guidelines that specified a process, and format, for the publication and consumption of off-chain data by smart contracts on the Cardano blockchain.

The Orcfax team developed the Cardano Open Oracle Protocol as a Catalyst funded research project that aimed to maximize the eUTXO model and leveraged design principles, CIP-31, and CIP-32 to prioritize a cost-sensitive, post-Vasil native method for publishing secure, signed, datums on-chain for reference input consumption by Cardano dApps.

The initial version of COOP was developed in collaboration with MLabs consultancy. The guidelines and specification in COOP are free, open-source, and can be implemented by any other project seeking to develop their own Cardano oracle feeds.

Shortly after this version was released, IOG discontinued support for both the Plutus Application Backend (PAB) and Plutus-Chain-Index. Both were critical components in the COOP v0 stack. Aware of the discontinued support, the Orcfax team partnered with technical consultants through MLabs to replace the components. Unfortunately, the plutus-chain-index component failed before a replacement could be rolled-out.

And so v0 was suspended in May of 2024.

More information pertaining to this failure can be found in both the public announcement and in the subsequent incident report.

Users and developers may find it informative to review the entire v0 Incidents repository as it contains many critical learnings from the implementation of v0.

Policy details

Links and information pertaining to policy IDs and smart contract addresses can be found in Policies.

In use

Minting policy identifiers were critical as Fact Statements were to be verified as having come from a known source. These identifiers also provided the ability to filter all of the UTXO at a given smart contract address and to filter out those sent by others to the same address.

Users were required to use the following information to identify the latest Facts published.

• Minting policy ID.
• Datum format, including:
  • Most recent (ValueReference -> PropertyValue[1] -> value), i.e. the largest POSIX timestamp compared to other Fact Statement datum,
  • Feed name, e.g. "ADA-USD".

Note: Users on preprod will find a volume of test data that was not ever retired as Orcfax previously used this space as a testing sandbox.

In this model, unconsumed reference inputs were those still available for smart contracts to use on-chain. Spending a UTXO with a reference input would render it unusable in a smart contract (though the data was still visible in the historical transaction). This process of consuming reference inputs was referred to as garbage collection or the retiring of Fact Statements.

During v0, Orcfax had a mainnet policy stipulating that two unspent Fact UTXO should remain on-chain at all times in order to provide users with continuous datum coverage.

Note: maintaining at least two datum on-chain gave smart contracts (and their developers) access to the most current datum, and the datum before that, for inspection. The POSIX timestamps denoting a valid-from and valid-through period could be inspected to ensure that they were still within a valid window.

For more information about the use of reference inputs and the inline datum utilized in COOP v0, see the relevant COOP design document.

v0 datum structure

All Fact Statements were structured as JSON-LD objects before being serialized into the Concise Binary Object Representation (CBOR used in Cardano transactions.

v0 JSON-LD schema

The Orcfax v0 datum was translated to on-chain CBOR from the following JSON schema (example given is from Sep 28, 2023):

{
    "@context": "https://schema.org",
    "type": "PropertyValue",
    "name": "ADA-USD|USD-ADA",
    "value": [0.249495, 4.008096354636367],
    "valueReference": [
        {
            "@type": "PropertyValue",
            "name": "validFrom",
            "value": 1695939870811
        },
        {
            "@type": "PropertyValue",
            "name": "validThrough",
            "value": 1695943470811
        }
    ],
    "identifier": {
        "propertyID": "Arkly Identifier",
        "type": "PropertyValue",
        "value": "urn:orcfax:4ae10640-10b9-4c23-af1d-c4a9dbd8938d"
    },
    "_:contentSignature": "40330ff2597c399ddaaab6c1dbaab52173ef82bf7f08d3ca84585ab5e76429a0"
}

Reading v0 datum on-chain

Orcfax Fact Statement datum were readable on-chain as Cardano Reference Inputs.

To have read the ADA-USD|USD-ADA mainnet feed, users were encouraged to check the latest transaction issued by the feed smart contract.

Where can I find the price data in the datum?

In this example we will use an off-chain datum. We will use this datum, within which the price data can be found in the following portion:

                            {
                                "fields": [
                                    {
                                        "int": 2540017902
                                    },
                                    {
                                        "int": 1.8446744073709552e+19
                                    }
                                ],
                                "constructor": 3
                            },
                            {
                                "fields": [
                                    {
                                        "int": 39369801260558197
                                    },
                                    {
                                        "int": 1.8446744073709552e+19
                                    }
                                ],
                                "constructor": 3
                            }
                        ]

The first “fields” (we’ll call it f1) conveys ADA-USD, the second (f2) conveys USD-ADA. Within each of these, the first int (we'll call it int1) represents a price pair.

With this in mind, f1, int1 gives the ADA-USD price as an integer (2540017902), and the second (f1, int2) gives the number of decimals as longint (1.8446744073709552e+19).

The same is true for f2, int1 which gives the price pair for USD-ADA as an integer; with f2, int2 giving the number of decimals.

Using Python, you can find out the price by executing the following:

price = p1 * pow(10, c_longlong(p2).value)

With the following results:

Reading v0 datum off-chain

The PyCardano SDK provided convenient helper functions for converting on-chain CBOR.

The Orcfax team created an open-source PyCardano demo script to assist users in reading and parsing the on-chain Orcfax datum.

This script converted the Cardano transaction's CBOR serialization to human and machine-readable JSON while simultaneously logging various details about the Datum as it went.

It's very easy to customize the configuration options of this script to match the requirements of another dApp.

This resource was made freely available under an open-source Apache v2.0 license so that users could test, integrate, and extend their own solutions by integrating Orcfax Fact Statement feeds.

demo script output:

2023-09-28T16:24:13Z INFO :: read_datum.py:264:read_datum() :: entering this script...
2023-09-28T16:24:13Z INFO :: read_datum.py:265:read_datum() :: oracle smart contract: addr_test1wrtcecfy7np3sduzn99ffuv8qx2sa8v977l0xql8ca7lgkgmktuc0
2023-09-28T16:24:15Z INFO :: read_datum.py:226:get_latest_utxo() :: inspecting '862' UTxOs
2023-09-28T16:24:15Z WARNING :: read_datum.py:254:get_latest_utxo() :: '7.00' hours since datum was published (1695943470811)
2023-09-28T16:24:15Z INFO :: read_datum.py:191:validate_utxo() :: inspecting the utxo for valid auth tokens
2023-09-28T16:24:15Z INFO :: read_datum.py:217:validate_utxo() :: the utxo is valid, it contains the correct auth token
2023-09-28T16:24:15Z INFO :: read_datum.py:79:display_utxo() :: (input) transaction id: 078d548b0ed91b95164d0baaf2b486161e06aab84483d99ed01a2180090ab0f3
2023-09-28T16:24:15Z INFO :: read_datum.py:80:display_utxo() :: (output) transaction addr: addr_test1wrtcecfy7np3sduzn99ffuv8qx2sa8v977l0xql8ca7lgkgmktuc0
2023-09-28T16:24:15Z INFO :: read_datum.py:81:display_utxo() :: (output) datum cbor:

590207d8799fa74840636f6e746578745268747470733a2f2f736368656d612e6f7267525f3a636f6e74656e745369676e61747572655840343033333066663235393763333939646461616162366331646261616235323137336566383262663766303864336361383435383561623565373634323961304a6964656e746966696572a34a70726f706572747949445041726b6c79204964656e74696669657244747970654d50726f706572747956616c75654576616c7565582f75726e3a6f72636661783a34616531303634302d313062392d346332332d616631642d633461396462643839333864446e616d654f4144412d5553447c5553442d41444144747970654d50726f706572747956616c75654576616c75659fd87c9f1a0003ce971bfffffffffffffffaffd87c9f1b000e3d57a771924e1bfffffffffffffff1ffff4e76616c75655265666572656e63659fa34540747970654d50726f706572747956616c7565446e616d654976616c696446726f6d4576616c75651b0000018adde4c05ba34540747970654d50726f706572747956616c7565446e616d654c76616c69645468726f7567684576616c75651b0000018ade1baedbff5820303443413030303148424559394b4b34343950314345513850483744544a5954d87a9f1b0000018ade1baedbff581c90b121aa6b689200adf7ed115040a96375d2b68e23633d6864c53a91ff

2023-09-28T16:24:15Z INFO :: read_datum.py:84:display_utxo() :: (output) Tx cost: 3.42214 ADA
2023-09-28T16:24:15Z INFO :: read_datum.py:151:decode_utxo() ::

{
  "@context": "https://schema.org",
  "type": "PropertyValue",
  "name": "ADA-USD|USD-ADA",
  "value": [
    0.249495,
    4.008096354636367
  ],
  "valueReference": [
    {
      "@type": "PropertyValue",
      "name": "validFrom",
      "value": 1695939870811
    },
    {
      "@type": "PropertyValue",
      "name": "validThrough",
      "value": 1695943470811
    }
  ],
  "identifier": {
    "propertyID": "Arkly Identifier",
    "type": "PropertyValue",
    "value": "urn:orcfax:4ae10640-10b9-4c23-af1d-c4a9dbd8938d"
  },
  "_:contentSignature": "40330ff2597c399ddaaab6c1dbaab52173ef82bf7f08d3ca84585ab5e76429a0"
}

2023-09-28T16:24:15Z INFO :: read_datum.py:152:decode_utxo() :: oracle datum identifier (internal): b'04CA0001HBEY9KK449P1CEQ8PH7DTJYT'
2023-09-28T16:24:15Z INFO :: read_datum.py:157:decode_utxo() :: oracle datum timestamp: 2023-09-28T23:24:30Z (1695943470811)
2023-09-28T16:24:15Z INFO :: read_datum.py:170:pretty_log_value() :: ADA-USD: 0.249495
2023-09-28T16:24:15Z INFO :: read_datum.py:170:pretty_log_value() :: USD-ADA: 4.008096354636367