The rules

The 30-day rule

Three states

Sealedday 0 to day 29

link opens itday 30, unopened

Openedshare delivered to the address chosen

Returnedshare sent back to the sender

Every envelope ends in exactly one of two states, and never changes again.

The return

On day 30 an unopened envelope can be returned. The return pays one address only, the sender's, so anyone is allowed to trigger it. Noshi does so every day for envelopes that reached their deadline, which is why the share comes back without you doing anything. You can also trigger it yourself from Sent and received.

What comes back is the share, not dollars. If a dividend or a split happened while it waited, it comes back with it.

What it guarantees

Before day 30, nobody can take the share back, the sender included.
Noshi has no key that can move a sealed share. The contract has no owner and no admin function.
After day 30, an unopened share can only go to the sender.

What it doesn't

The link is the envelope. Anyone who has it can open the envelope before day 30, so a forwarded message or a photo of the QR code is enough to lose it, and Noshi can't tell who opened it. Opening also needs an address: the person you send it to must have a wallet address by day 30.

The companies that issue the stock tokens keep their own powers over their tokens: they can pause a token or block an address, including the Noshi contract, and a sealed share would wait until they lift it. Paxos, which issues USDG, can freeze an address too. Those powers apply to every holder and Noshi can't override them.