Predeployed contract to verify Oracle responses
Oracle-contract is a predeployed smart-contract set running on each SKALE Chain which can verify Oracle responses.
{
"cid": 1,
"uri": "http://worldtimeapi.org/api/timezone/Europe/Kiev",
"jsps": [ "/unixtime", "/day_of_year", "/xxx" ],
"trims": [ 1, 1, 1 ],
"post": "/time_answer",
"time": 1642521456593,
"rslts": [ "164252145", "1", null ],
"sigs": [
"0:fd4dde03a49aa83dcad8fe4e1e3e7b51e827c35d0339b047c71dd2a5673ac844:695b94e047f7310143a238d8b61f22ea60dcc3960d897d6dc57f212b91efe6f1",
"0:fd4dde03a49aa83dcad8fe4e1e3e7b51e827c35d0339b047c71dd2a5673ac845:695b94e047f7310143a238d8b61f22ea60dcc3960d897d6dc57f212b91efe6f1",
"0:fd4dde03a49aa83dcad8fe4e1e3e7b51e827c35d0339b047c71dd2a5673ac846:695b94e047f7310143a238d8b61f22ea60dcc3960d897d6dc57f212b91efe6f2",
"0:fd4dde03a49aa83dcad8fe4e1e3e7b51e827c35d0339b047c71dd2a5673ac847:695b94e047f7310143a238d8b61f22ea60dcc3960d897d6dc57f212b91efe6f3",
"0:fd4dde03a49aa83dcad8fe4e1e3e7b51e827c35d0339b047c71dd2a5673ac848:695b94e047f7310143a238d8b61f22ea60dcc3960d897d6dc57f212b91efe6f4",
"0:fd4dde03a49aa83dcad8fe4e1e3e7b51e827c35d0339b047c71dd2a5673ac849:695b94e047f7310143a238d8b61f22ea60dcc3960d897d6dc57f212b91efe6f5",
null,
null,
null,
null,
null,
null,
null,
null,
null,
null
]
}Each node of SKALE chain get an Oracle response, removes part after "rslts":[...],, combine to one string without spaces, get a KECCAK256 hash of this string and sign this string by ECDSA signature of this node
Example object to sign:
{
"cid": 1,
"uri": "http://worldtimeapi.org/api/timezone/Europe/Kiev",
"jsps": [ "/unixtime", "/day_of_year", "/xxx" ],
"trims": [ 1, 1, 1 ],
"post": "/time_answer",
"time": 1642521456593,
"rslts": [ "164252145", "1", null ],Combined to string:
{"cid":1,"uri":"http://worldtimeapi.org/api/timezone/Europe/Kiev","jsps":["/unixtime","/day_of_year","/xxx"],"trims":[1,1,1],"post":"/time_answer","time": 1642521456593,"rslts":["164252145","1",null],If n - t + 1 ECDSA signatures provided - Oracle response is signed
where:
n - number of nodes in SKALE chain
t - threshold number for BLS signature ( 2/3n + 1 )
- Clone this repo and enter the repo
- run
cd oracle-contract/ - run
yarn install
The .env file in the oracle-contract folder should include the following variables:
ENDPOINT="your mainnet RPC url, it also can be an infura endpoint"
PRIVATE_KEY="your private key for mainnet"
GASPRICE="preferred gas price (optional param)" - deploy production upgradeable version to custom network:
yarn deploy --network custom- deploy production not upgradeable version to custom network:
yarn deploy-not-upgradeable --network custom- deploy test version to custom network:
yarn deploy-test --network custom- deploy test not upgradeable version to custom network:
yarn deploy-test-not-upgradeable --network customyarn test- Install
@skalenetwork/oracle-interfacesnpm package by npm or yarn - Import
IOracle.solin your Solidity smart contract - Import a predeployed address
0xd205aC1e00000000000000000000000000000000in your Solidity smart contract - Run verification
// SPDX-License-Identifier: AGPL-3.0
pragma solidity 0.8.13;
import "@skalenetwork/oracle-interfaces/IOracle.sol";
contract VerifyOracleResponses {
address public constant ORACLE_ADDRESS = 0xd205aC1e00000000000000000000000000000000;
function checkOracleResponse(
IOracle.OracleResponse memory response
)
public
{
require(IOracle(ORACLE_ADDRESS).verifyOracleResponse(response), "Verification is failed");
}
}To see how to send Oracle request and get Oracle responses please go to oracle-demo
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