Created

Feb 9, 2022 12:34 PM

Creator

Nicola

Stage

Still Valid

If we have a way to prove that two merkle trees are different then we can solve the following problems.

If we solve problem 1, we don't have to solve problem 2.

# Storage IPFS hashes

**Goal:**

Store data via IPFS hash

**Setting:**

- Client gives IPFS hash to miner
- Miner turns it into a PieceCID
- Miner makes the deal with IPFS CID field and PieceCID field
- When a user gets the file back from the miner, they can check if the file matches the IPFS CID
- If the IPFS CID is not matched, then they can post a proof that this mapping was incorrect

**Actual proof:**

- Find the branch of the IPFS DAG and the branch of the PieceCID where the data differ
- Generate a merkle proof for each
- (Option: if the proof is too big: SNARK those proofs)
- Send proof on-chain

Next steps:

SNARK Friendly Data Structures: Simpler IPLD for SNARK friendly circuits

# Poseidon CommD on-chain for faster SnapDeals

**Goal:**

Make the proofs for SnapDeals to be super cheap by having CommD generated with Poseidon without the client running Poseidon.

**Setting:**

- Client gives ShaCommD to miner
- Miner turns it into PoseidonCommD
- Miner makes the deal with PoseidonCommD and ShaCommD
- When user gets the file back, they can check if their file matches ShaCommD
- If the file does not match ShaCommD, they can post a proof

**Actual proof:**

- Find the branch of PoseidonCommD and the branch of ShaCommD where the branch disagree
- Generate merkle tree proof for each
- (Option: if the proof is too big: SNARK those proof)
- Send proof on chain

**Cons:**

- Who puts the collateral to be slashed? can we reuse the deal collateral?