Protocol
Gasless relayer
Privacy has a funny failure mode: you shield everything, then pay gas from a public wallet and hand the whole thing back. The gasless relayer closes that gap.
The problem
A shielded transaction still costs gas, and gas has to come from somewhere. If it comes from your own funded address, that address is now tied to the shielded action — and it probably traces back to a KYC’d exchange withdrawal. The privacy is gone at the last step.
How the relayer works
- You build and sign a shielded transaction locally. It never reveals your amounts.
- You hand it to a relayer instead of broadcasting it yourself.
- The relayer pays the gas and submits it on-chain.
- The relayer’s fee is taken from your shielded balance inside the same proof — so you never touch a public gas balance at all.
Trust model
Be precise about what a relayer can and cannot do:
| A relayer can | A relayer cannot |
|---|---|
| Choose to include or drop your transaction | See your amounts or positions |
| See that some shielded tx passed through it | Steal funds — it never holds them |
| Charge a fee | Deanonymize the note owner |
Censor, not seize
The relayer’s only power is to ignore you. Cowl mitigates this with a set of independent relayers — if one censors, route around it. No relayer can move or read your funds.