Question: Is there an existing solidity verifier for proofs created with @ethereumjs/trie?

[sebastiendan]

Hi,

In combination with using @ethereumjs/trie in the browser to create merkle proofs against transaction tries, I'm looking for a compatible on-chain verifier. It's pretty hard to find an existing contract out there that would work out of the box with the type/format of merkle proofs created with @ethereumjs/trie (so many unfinished/abandoned projects).

Would you know if such a compatible on-chain verifier (contract) exist?

Thanks!

[jochem-brouwer]

This seems to me what you are looking for: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/cryptography/MerkleProof.sol

[sebastiendan]

@jochem-brouwer This is for standard merkle trees only, no? I was expecting the verification of merkle proofs for merkle patricia tries to be incompatible for the one for merkle trees.

[jochem-brouwer]

This should work also for MPTs. The gotcha here is that this is a "normal" Merkle tree but the data inside the tree is encoded as Patricia tree.

[sebastiendan]

@jochem-brouwer The verifier from OpenZeppelin expects a proof as a bytes32[]. The proofs I get with @ethereumjs/trie are 307B large. Is there an extra step I'm missing?

[jochem-brouwer]

I might have been a bit too fast to reply here, but I will investigate a bit further for you, because I would expect that an EVM/Solidity implementation of MPT proofs are readily available.

[sebastiendan]

Ok thanks. In addition, we've found this related issue on OpenZeppelin contract repo.

[jochem-brouwer]

(have converted to a discussion :) )

[sebastiendan]

@jochem-brouwer Any luck so far with your research? So far we're only finding verifier contracts that work with specific formats expected from provers.

[sebastiendan]

FYI we were able to use this Solidity verifier to verify Merkle proofs of transaction tries made with @ethereumjs/trie:
https://github.com/lorenzb/proveth

We had to not use trie.createProof which is essentially finding the path in the trie and serializing the nodes in the path, and rather use the trie.findPath function along with a node => node.raw() map.