Police Oracle

Inspiration

We are inspired about cryptography-based solutions, off-chain solutions, zero-knowledge proof solutions. They are very cool, allowing to do "magic".

What it does

Improving Communication & Infrastructure

The solution continuously checks for "bad" transactions happening in the blockchain, such an interaction with a mixer. Once it finds one, it immediately notifies subscribed smart contracts about such a transaction, providing zero-knowledge proof for transparency and trustlessness.

Solution developed for the Aragon sponsor.

How we built it

Ethers.js + TypeScript for off-chain script, Solidity for smart contracts, implementing Aragon's Oracle standard. It was actually tough. Really tough. It's hard to prove to a contract that a transaction occurred. You need to pass the whole transaction, then serialise. (we did opposite - we pass serialised data which we then deserialise).

Challenges we ran into

Lack of motivation when we thought it was not possible =) However we quickly fixed it by proving it was possible.

Accomplishments that we're proud of

We did what we thought ourselves was impossible.

What we learned

You cannot really serialise a transaction inside a solidity, because the RLP serialisation that takes place is hard to implement there. It's better to deserialise an already serialized message and work our way from it.