42 lines
1.5 KiB
Solidity
42 lines
1.5 KiB
Solidity
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pragma solidity ^0.5.0;
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/**
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* @title MerkleProof
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* @dev Merkle proof verification based on https://github.com/ameensol/merkle-tree-solidity/blob/master/src/MerkleProof.sol
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* Source: https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/MerkleProof.sol
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*/
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library MerkleProof {
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/**
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* @dev Verifies a Merkle proof proving the existence of a leaf in a Merkle tree. Assumes that each pair of leaves
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* and each pair of pre-images are sorted.
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* @param _proof Merkle proof containing sibling hashes on the branch from the leaf to the root of the Merkle tree
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* @param _root Merkle root
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* @param _leaf Leaf of Merkle tree
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*/
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function verifyProof(
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bytes32[] memory _proof,
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bytes32 _root,
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bytes32 _leaf
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)
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internal
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pure
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returns (bool)
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{
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bytes32 computedHash = _leaf;
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for (uint256 i = 0; i < _proof.length; i++) {
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bytes32 proofElement = _proof[i];
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if (computedHash < proofElement) {
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// Hash(current computed hash + current element of the proof)
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computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
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} else {
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// Hash(current element of the proof + current computed hash)
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computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
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}
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}
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// Check if the computed hash (root) is equal to the provided root
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return computedHash == _root;
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}
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}
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