If you lose control of a device

This page is for any device that holds CHANNEL and is no longer in your hands: lost, taken, or out of reach for any other reason. It says what is at risk, what to do first, and what CHANNEL can and cannot do.

What is at risk

What the device holds. Every profile on it, with its conversations, contacts and pictures, can be read by whoever can open the device and CHANNEL. The device's own passcode comes first. The app PIN and Lock This Profile add a PIN on top. See Privacy on this device.
What still arrives. Until it is revoked or erased, the device keeps receiving new messages for the profiles on it.
Writing as you. Whoever can open it can send messages from those profiles, and your contacts see them as yours.
Text codes. If it is a phone, whoever has its SIM card receives the text codes sent to your number.

In the first hour

Do these from a device you still have.

If the profile is shared with the missing device, open Shared Profiles on a device you still have and choose Revoke on the missing device's row. People stop writing to it at once, and it takes nothing more from your other devices.
To have it erase CHANNEL, choose Revoke and Erase on its row (on Android, Remove and erase or Erase). It is removed at once, and the instruction to erase reaches it when it is switched on and online within thirty days.
Use the device's own finder: Find My for an iPhone, iPad or Mac, Find Hub for Android. Find my device on Windows locks a device. An erase runs when the device next reaches the internet.
If it is a phone, ask your phone company to block the SIM card and give you a new one.
Tell the people who matter, by another route, that the device is gone.

Look at Shared Profiles on every device you still have, and revoke any device you do not recognise.
Change any PIN you also use somewhere else, if it could have been seen. A PIN stays on the device where you set it, so changing it here does not change it on the missing device.
If you cannot trust the profile any more, use Start Fresh under Shared Profiles in the iPhone and iPad app. It makes a new, empty profile with your contacts' names and asks each of them to accept it. The old profile is not touched. Tell your contacts to check it is really you before they trust it. See Settings.
Make a new backup on a device you hold. See Backups.

What CHANNEL does for you

Revoke stops the missing device receiving the profile's messages, and your contacts stop writing to it.
Revoke asks for the app PIN when one is set, so whoever holds an unlocked device cannot revoke your others without it.
A PIN is checked by the device's security chip where it has one, so a copy of CHANNEL's files cannot be used to try guesses elsewhere.
No PIN leaves the device. Sharing a profile never sends its PIN to another device.
CHANNEL's data is left out of the phone's own cloud backup, so restoring that backup elsewhere does not bring back your messages.
There is no account, so there is nothing on a server that someone else could sign in to.

What CHANNEL cannot do

It cannot take back what was already seen or copied before the device was locked or erased.
It cannot reach a device that stays offline. An erase from CHANNEL or from the device's finder waits until the device connects, and one from CHANNEL waits at most thirty days.
It cannot stop the SIM card receiving text codes. Only your phone company can.

Before it happens

A passcode on every device, and its finder turned on.
An app PIN, and Lock This Profile on any profile that matters.
A backup kept away from the device. See Backups.
A profile that matters is safest on one device you keep with you. See Settings.