The receipt should come from the person who received it

This is a submission for Weekend Challenge: Generosity Edition

What I Built

Every donation platform proves the same single fact: money left your account. The fact you actually care about is the second one, that it reached a person, and the receipt for the first is issued by the organisation holding the money. The thing you're trusting and the thing producing the evidence are the same thing.

Cairn changes who issues the receipt.

You lock SOL in an escrow no intermediary can open. The only thing that moves it is a signature from the recipient's own wallet, and that transaction carries the hash of a recording where they say, in their own words, what they received. The receipt comes from the person at the end of the chain, and the chain welds it to the transfer.