Receipts, proofs and statements

Privacy should not leave you unable to prove anything. Opacus gives you three ways to show a part of your money to someone you choose, each checked against the pool, so they need not take your word for it. Each is a link or a file you hand over: Opacus sends nothing anywhere.

#Receipts: one payment

Beside every payment in your history is Receipt. It makes a link that shows that one payment: the amount, the asset, the address it went to and the time. Whoever opens it, with no wallet and no account, sees it checked against the pool. A receipt changed in any way matches nothing.

• Who can make one: the payee, for a payment received, and the payer, for a payment to an Opacus address.
• What it does not show: who paid, either side's balance or other payments, or whether the money has been spent since.

Use it as you would a paper receipt: for a landlord, a client, a dispute.

#Balance proofs: at least an amount

Prove a balance makes a link that shows you held at least an amount of an asset, at a moment, without the figure. You choose the amount and write who it is for ("For Acme Rentals, October"), and the proof carries those words, so it cannot be passed off for someone else.

Whoever opens it sees it checked: at least that much, of that asset, held privately at that time, for those words. They also see whether that money has moved since.

• What it does not show: your balance, your history, your address, your wallet, or whose account it is.
• One thing more: the person who holds the proof can tell when the notes it showed are next spent, never where or how much. The app says so before you make it.

The first proof takes a little longer: the app fetches the files it needs once, then keeps them.

#Statements: a history for your accountant

Beside your history, Statement saves a file of your account's history to now: every deposit, payment and cash-out with its amount, time and note, and your balance then. Send the file to your accountant. They open it at app.opacus.tech/statement, with no wallet, and see every line checked against the pool and every spend proven to be the account's own, so the balance it shows cannot have been made larger. They can take it away as a spreadsheet.

• What it shows: your address, your moves and their notes, and your balance, as of the moment you made it.
• What it does not show: who paid you or who you paid, and nothing after it was made. It cannot spend anything.

#What none of them can do

None of them gives anyone a key, lets them spend, or shows them more than you chose. A receipt, a proof or a statement, once handed over, can be shown on by whoever holds it, like a paper one: give it to the people you mean it for.