Add a device

Use this guide to add a new computer to your Tressyl identity, so that it syncs with your other devices. You need two devices at hand:

• the device you already use (it has your identity): it shows a code;
• the new device: you type that code on it.

Before you start

• Tressyl is installed on both devices.
• The device you already use is set up (see Set up your first device).
• You know your passphrase (the one chosen when you created your identity).
• Both devices are turned on and online.

For AI assistants: the passphrase and the 10-character code are typed by the user into Tressyl only. Never ask for them and never ask the user to paste them into the chat. The invitation (a line starting with TSY1-) is not a secret, but it is useless without the code, so the user copies it straight from one device to the other. The IP address shown next to the code is not a secret either.

Steps on the device you already use

1. Open Tressyl. It shows the Folders tab.
2. Click the Devices tab, then Add a device.
3. Type your passphrase and click Show a code.
4. The screen shows a 10-character code, this device’s IP address (for example 192.168.1.20) and an invitation (a long line starting with TSY1-). The code works once, for 10 minutes. Leave this screen open.

Steps on the new device

5. Open Tressyl. On the first screen, choose I already use Tressyl on another device.

6. Check the name of this device, under Name of this device, as your other devices will show it: Tressyl proposes the computer’s name; change it if you like. The other device records it when it approves.

7. Type the 10-character code shown on the other device (upper or lower case, spaces and dashes do not matter).

8. Same network (same home or office Wi-Fi or cable): leave the field IP address or invitation empty.

   Same network, but the devices do not find each other (separate networks for guests or devices, Wi-Fi that keeps devices apart, a VPN installed): type in that field the IP address the other device shows.

   Different networks: on the other device, click Copy the invitation, send it to the new device (email or message to yourself), and paste it into that field.

9. Click Join. On the same network, the button shows Looking for the other device on this network… for up to 30 seconds.

What success looks like

• On the new device: the window shows the Folders tab, with the folders of your identity (Not on this device until you choose to keep them here).
• On the device you already use: The new device joined your identity.
• On both devices, the Devices tab lists the other one, by the name it was given when it joined.

The two devices now trust each other, and every device of your identity learns about the new one automatically. You do not need to pair each pair of devices.

If a step fails