EIP-7503: Zero-Knowledge Wormholes - Private Proof of Burn (PPoB)

[keyvank]

@MicahZoltu

We currently only have the last 128 blockhashes in the EVM. There is a stagnant EIP somewhere that proposes storing all blockhashes in state, which would be necessary for this to work. Presumably if this went through then that EIP also would go through as a dependency.

If this is going to be implemented on the base layer, then I think the best option is to not rely on EVM-providen roots, and build and maintain an additional tree with a ZK-friendly hash function on Ethereum clients.

@MicahZoltu

One downside of this strategy is that the anonymity set shrinks over time. If you mint at block 20,000,000, then your anonymity set is all accounts with ETH and no transactions where the ETH was transferred into the account after this change goes live and before block 20,000,000. However, over time the set of accounts where the ETH doesn’t move will trend towards only those which were actual burns, thus your anonymity set ends up (eventually) being similar to contract layer tools like Tornado.

This is actually very convincing and sad, I thought the anonymity set would be bigger.