Send a file privately to someone
Rolling out. The server side of Send files is in this version of Reelhost. The buttons for it in Signal arrive in a Signal update, so you may not see it in your app yet.
Send files moves one file from one person to another through the sender's own server. Reelhost only carries it: nothing goes to a Reelhost server, and nothing is saved for you. The other person saves it on their own device.
- Set up once. Each person picks a passphrase of at least 8 characters and is shown a recovery code, once. The passphrase and code make the keys that lock your files; neither is kept anywhere. Lose both and what's waiting can't be opened.
- Encrypted while it waits. The file is encrypted on your server before it's saved there and is only opened for the people it was sent to. Your keys stay open for 15 minutes of not using it, then you type your passphrase again.
- It has an end date. 7 days unless the sender picks 1 to 30. The file is deleted (overwritten first) when everyone named has picked it up, when the sender takes it back, or when the date passes. The sender's computer must be on for the other person to pick it up.
- Links. The sender can make a link for someone outside the household: it can have a password, ends in 7 days unless the sender picks up to 30, works a set number of times (once unless the sender picks more), and can be ended at any time. The page shows the file's name and size first; the file is only sent when the button is pressed, so a chat app that previews the address can't use it up. Links work through your web address while Signal from away is on.
- Safer by default. Programs and scripts are refused (unless an admin allows them, and then they are never sent by link). Archives and files of unknown type are held back from links until the sender confirms they trust them. Files are always sent as downloads and never opened by Reelhost. Kid profiles can receive files but can't send or make links unless an admin allows it.
- To your own other devices. Choose My other devices to send a file from the device you're on to your other phones and computers where you're signed in to Signal. Each device picks it up on its own, once; the waiting copy is deleted when every one of those devices has it, or on its end date, whichever comes first. Devices you signed out, or that the server's owner blocked, aren't included. To pick it up you open Send files on that device and type your passphrase, the same as for a file from someone else.
- A link and nobody else. You don't have to name anyone: send a file for a private link only. It's the same link as above (password, end date, a set number of uses, ended at any time), and the file is deleted after the last use, when you end the link, or on its end date.
- Big files and bad Wi-Fi. A file goes up in pieces, already encrypted. If the connection breaks, Resume carries on from the last whole piece instead of starting again. The whole file is checked at the end (its size and fingerprint must match what you chose), and a file that doesn't match is thrown away. An upload nobody touches for 2 days is deleted.
- Say no. If you don't want what someone sent, choose Decline: your copy is deleted and the sender sees that you declined. The file goes when nobody else is waiting for it.
- Limits. An admin sets the largest file and how much can wait in total (at home only). Uploads in progress count toward the total.
- Take it back. The sender can take a file back, remove one person (the file is locked again with a new key they never had), end a link, or use Revoke everything to delete all their waiting files and end all their links at once. The sender's own history of what was sent, picked up and ended is theirs to read; it's kept 90 days and never leaves the server.
Activity lists on the server say that a file was sent, never its name. When you remove Reelhost, the waiting files, keys, links and history are deleted. Files already picked up are on the other person's device and aren't touched.