Is there a way for smart contract on RSK to fetch on-chain data on Bitcoin not depending on trusted oracles?
I just found a proposal called Open Bitcoin blockchain oracle (RSKIP220) which will be implemented from the IRIS upgrade but couldn't find any resources on it. Does anybody know where I can find it?
Blog post mentioning RSKIP220: https://blog.rsk.co/noticia/iris-v3-0-0-is-here-what-you-need-to-know-about-rsk-upcoming-network-upgrade/
Here is a working example of how to use Bridge methods to access Bitcoin blocks. This code has been tested in RSK Testnet.
Bridge.sol:
// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;
interface Bridge {
function getBtcBlockchainBestChainHeight ( ) external view returns ( int );
function getStateForBtcReleaseClient ( ) external view returns ( bytes memory);
function getStateForDebugging ( ) external view returns ( bytes memory );
function getBtcBlockchainInitialBlockHeight ( ) external view returns ( int );
function getBtcBlockchainBlockHashAtDepth ( int256 depth ) external view returns ( bytes memory );
function getBtcTxHashProcessedHeight ( string calldata hash ) external view returns ( int64 );
function isBtcTxHashAlreadyProcessed ( string calldata hash ) external view returns ( bool );
function getFederationAddress ( ) external view returns ( string memory );
function registerBtcTransaction ( bytes calldata atx, int256 height, bytes calldata pmt ) external;
function addSignature ( bytes calldata pubkey, bytes[] calldata signatures, bytes calldata txhash ) external;
function receiveHeaders ( bytes[] calldata blocks ) external;
function receiveHeader ( bytes calldata ablock ) external returns ( int256 );
function getFederationSize ( ) external view returns ( int256 );
function getFederationThreshold ( ) external view returns ( int256 );
function getFederatorPublicKey ( int256 index ) external view returns ( bytes memory);
function getFederatorPublicKeyOfType ( int256 index, string calldata atype ) external returns ( bytes memory);
function getFederationCreationTime ( ) external view returns ( int256 );
function getFederationCreationBlockNumber ( ) external view returns ( int256 );
function getRetiringFederationAddress ( ) external view returns ( string memory );
function getRetiringFederationSize ( ) external view returns ( int256 );
function getRetiringFederationThreshold ( ) external view returns ( int256 );
function getRetiringFederatorPublicKey ( int256 index ) external view returns ( bytes memory);
function getRetiringFederatorPublicKeyOfType ( int256 index,string calldata atype ) external view returns ( bytes memory);
function getRetiringFederationCreationTime ( ) external view returns ( int256 );
function getRetiringFederationCreationBlockNumber ( ) external view returns ( int256 );
function createFederation ( ) external returns ( int256 );
function addFederatorPublicKey ( bytes calldata key ) external returns ( int256 );
function addFederatorPublicKeyMultikey ( bytes calldata btcKey, bytes calldata rskKey, bytes calldata mstKey ) external returns ( int256 );
function commitFederation ( bytes calldata hash ) external returns ( int256 );
function rollbackFederation ( ) external returns ( int256 );
function getPendingFederationHash ( ) external view returns ( bytes memory);
function getPendingFederationSize ( ) external view returns ( int256 );
function getPendingFederatorPublicKey ( int256 index ) external view returns ( bytes memory);
function getPendingFederatorPublicKeyOfType ( int256 index, string calldata atype ) external view returns ( bytes memory);
function getLockWhitelistSize ( ) external view returns ( int256 );
function getLockWhitelistAddress ( int256 index ) external view returns ( string memory);
function getLockWhitelistEntryByAddress ( string calldata aaddress ) external view returns ( int256 );
function addLockWhitelistAddress ( string calldata aaddress, int256 maxTransferValue ) external returns ( int256 );
function addOneOffLockWhitelistAddress ( string calldata aaddress, int256 maxTransferValue ) external returns ( int256 );
function addUnlimitedLockWhitelistAddress ( string calldata aaddress ) external returns ( int256 );
function removeLockWhitelistAddress ( string calldata aaddress ) external returns ( int256 );
function setLockWhitelistDisableBlockDelay ( int256 disableDelay ) external returns ( int256 );
function getFeePerKb ( ) external view returns ( int256 );
function voteFeePerKbChange ( int256 feePerKb ) external returns ( int256 );
function updateCollections ( ) external;
function getMinimumLockTxValue ( ) external view returns ( int256 );
function getBtcTransactionConfirmations ( bytes32 txHash, bytes32 blockHash, uint256 merkleBranchPath, bytes32[] calldata merkleBranchHashes ) external view returns ( int256 );
function getLockingCap ( ) external view returns ( int256 );
function increaseLockingCap ( int256 newLockingCap ) external returns ( bool );
function registerBtcCoinbaseTransaction ( bytes calldata btcTxSerialized, bytes32 blockHash, bytes calldata pmtSerialized, bytes32 witnessMerkleRoot, bytes32 witnessReservedValue ) external;
function hasBtcBlockCoinbaseTransactionInformation ( bytes32 blockHash ) external returns ( bool );
function registerFastBridgeBtcTransaction ( bytes calldata btcTxSerialized, uint256 height, bytes calldata pmtSerialized, bytes32 derivationArgumentsHash, bytes calldata userRefundBtcAddress, address liquidityBridgeContractAddress, bytes calldata liquidityProviderBtcAddress, bool shouldTransferToContract ) external returns ( int256 );
function getActiveFederationCreationBlockHeight ( ) external view returns ( uint256 );
function getBtcBlockchainBestBlockHeader ( ) external view returns ( bytes memory );
function getBtcBlockchainBlockHeaderByHash ( bytes32 btcBlockHash ) external view returns ( bytes memory );
function getBtcBlockchainBlockHeaderByHeight ( uint256 btcBlockHeight ) external view returns ( bytes memory );
function getBtcBlockchainParentBlockHeaderByHash ( bytes32 btcBlockHash ) external view returns ( bytes memory);
}
QueryDemo.sol:
// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;
import "./Bridge.sol";
contract QueryDemo {
int public bestChainHeight;
bytes public returned;
bytes32 public headerHash;
function reverse(uint256 input) internal pure returns (uint256 v) {
v = input;
// swap bytes
v = ((v & 0xFF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00) >> 8) |
((v & 0x00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF) << 8);
// swap 2-byte long pairs
v = ((v & 0xFFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000) >> 16) |
((v & 0x0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF) << 16);
// swap 4-byte long pairs
v = ((v & 0xFFFFFFFF00000000FFFFFFFF00000000FFFFFFFF00000000FFFFFFFF00000000) >> 32) |
((v & 0x00000000FFFFFFFF00000000FFFFFFFF00000000FFFFFFFF00000000FFFFFFFF) << 32);
// swap 8-byte long pairs
v = ((v & 0xFFFFFFFFFFFFFFFF0000000000000000FFFFFFFFFFFFFFFF0000000000000000) >> 64) |
((v & 0x0000000000000000FFFFFFFFFFFFFFFF0000000000000000FFFFFFFFFFFFFFFF) << 64);
// swap 16-byte long pairs
v = (v >> 128) | (v << 128);
}
function clear() public {
headerHash =0;
returned = "";
}
function getBridge() private pure returns (Bridge) {
return Bridge(address(0x01000006));
}
function getBtcBlockchainBestChainHeight() public {
bestChainHeight = getBridge().getBtcBlockchainBestChainHeight();
}
// getBtcBlockchainBlockHashAtDepth:
// This method throws an OOG because getBtcBlockchainBlockHashAtDepth() cannot be called
// from a contract. Use getBtcBlockchainBestChainHeigh() and getBtcBlockchainBlockHeaderByHeight()
//
function storeBtcBlockchainBlockHashAtDepth(int256 depth) public {
returned = getBridge().getBtcBlockchainBlockHashAtDepth(depth);
}
function getHeaderHash(bytes memory x) private pure returns(bytes32) {
bytes32 h = sha256(x);
bytes32 h2 = sha256(abi.encodePacked(h));
return bytes32(reverse(uint256(h2))); // to show it like Bitcoin does on the debugger
}
function computeHeaderHash() private {
headerHash = getHeaderHash(returned);
}
function storeBtcBlockchainBestBlockHeader ( ) external {
returned = getBridge().getBtcBlockchainBestBlockHeader();
computeHeaderHash();
}
function getBtcBlockchainBestBlockHeader ( ) external view returns (bytes memory) {
return getBridge().getBtcBlockchainBestBlockHeader();
}
function storeBtcBlockchainBlockHeaderByHash ( bytes32 btcBlockHash ) external {
returned = getBridge().getBtcBlockchainBlockHeaderByHash ( btcBlockHash );
computeHeaderHash();
}
function getBtcBlockchainBlockHeaderByHash ( bytes32 btcBlockHash ) external view returns (bytes memory) {
return getBridge().getBtcBlockchainBlockHeaderByHash ( btcBlockHash );
}
function storeBtcBlockchainBlockHeaderByHeight ( uint256 btcBlockHeight ) external {
returned = getBridge().getBtcBlockchainBlockHeaderByHeight (btcBlockHeight);
computeHeaderHash();
}
function getBtcBlockchainBlockHeaderByHeight ( uint256 btcBlockHeight ) external view returns(bytes memory ret) {
return getBridge().getBtcBlockchainBlockHeaderByHeight (btcBlockHeight);
}
function storeBtcBlockchainParentBlockHeaderByHash ( bytes32 btcBlockHash ) external {
returned = getBridge().getBtcBlockchainParentBlockHeaderByHash ( btcBlockHash);
computeHeaderHash();
}
function getBtcBlockchainParentBlockHeaderByHash ( bytes32 btcBlockHash ) external view returns(bytes memory ret) {
return getBridge().getBtcBlockchainParentBlockHeaderByHash ( btcBlockHash);
}
function testGetParentParentHeader() public view returns(bytes memory ret) {
bytes memory x = getBridge().getBtcBlockchainBlockHeaderByHeight (2064695);
bytes32 h =getHeaderHash(x);
// now the has has been computed. Use the has to get the parent block header
ret=getBridge().getBtcBlockchainParentBlockHeaderByHash ( h);
}
function testStoreGetParentHeader() public {
returned = getBridge().getBtcBlockchainBlockHeaderByHeight (2064695);
computeHeaderHash();
// now the has has been computed. Use the has to get the parent block header
returned = getBridge().getBtcBlockchainParentBlockHeaderByHash ( headerHash);
computeHeaderHash();
}
}