⚠ Not yet reviewed by a lawyer. Sourced information, to be confirmed.

Signal groups: creating and configuring groups

Signal groups: overview

Terms used here: the groups (public, airlock, trusted), the roles (HR, keyholder…) and the vocabulary.

Naming groups

A short, coded name helps you find your way and replace groups without confusion. Fictional example: MVT-CTY-4K9-Medic. The trusted group and its sub-groups form a family, which shares the same ID: MVT-CTY-4K9-General, MVT-CTY-4K9-Medic, MVT-CTY-4K9-Legal. In the name, the trusted group is simply called General: a neutral word that doesn't reveal a level.

Part	Meaning	Advice
MVT	The movement or campaign	Optional
CTY	The city or area (three letters)	Readable: the police already know where protests happen
4K9	ID of the family (the trusted group and its sub-groups)	Randomly drawn, never sequential (1, 2, 3 gives away how many families have existed or been lost). Family lost: all its groups are replaced under a new ID. A single sub-group lost: it is recreated in the same family, with a number (MVT-CTY-4K9-Medic2)
Medic	The topic, role or team	Stay vague for sensitive roles ("Logistics" rather than the details of the equipment)

Discreet variant, if you also want to hide the movement, the city and the topics: random IDs only, for example 4K9-T2.

• 4K9 replaces MVT-CTY-4K9: the family ID, on its own.
• T2 replaces Medic: a second ID for the topic, also drawn at random, and the same in every family (T2 always means the medics, for example).
• The mapping (which ID for which city, which topic) is memorised or kept in the register, never in the groups. Each member knows what their own groups are for, and that is enough.

• The cost: it is harder to find your way. Keep a clear name unless you really need discretion.

• Avoid words that reveal a level ("vetted", "core", "orga"): they flag the important groups on a screen or a screenshot.

• On a seized phone, the shared ID shows which groups belong together: their shared members would show it anyway, and the family is replaced in one go.
• Pick a name that won't need changing: every change of name or description shows up as an alert in the chat.¹
• Keep a register of active and lost families and groups, and of who is in which group (by activist name), held by two or three people, outside the groups: it is what lets you remove someone everywhere within minutes.

Setting up the groups

Group	Size	Disappearing messages	Keyholders	Entry	Description
Public group	Up to 1,000 (Signal's maximum)2	4 weeks (the maximum)3	2 or 3, plus secretaries to announce meetings; only admins post	Link allowed (the one exception), no approval, reset if needed; or direct add	Short charter and a link to this site
Airlock group	5 to 15 people	1 week: its lifetime; it holds nothing sensitive	The secretary who announces it, and one other person	Added directly by the secretary, after a private sign-up; no link	Empty
Trusted group	25 preferably, 50 at most	1 week; a few hours, as short as possible, from a few hours before the action	2 or 3, not the same everywhere	Added directly by HR; no link	Charter only
Sub-group	5 to 15; under 10 if sensitive	1 week; 1 day if sensitive, a few hours on action days	2	Added directly by a keyholder; no link	Charter only
Liaison group	4 to 8 people: 2 liaisons per family	1 week; a few hours on action days	2, from different families	Added directly, with the agreement of each family's HR; no link	Charter only
Temporary group	The people present	A few hours for a day; the length of the mobilisation otherwise	The person who created it and one other	Added directly, in person, by whoever created it; no link or QR code	Empty

A group is set up empty, before the first invitation: the message timer only covers new messages.³

1. Create the group alone or with your co-keyholder → name following the naming scheme, no photo.
2. Disappearing messages → the timer from the table, from creation.³
3. Permissions → to set at creation (group settings › permissions). Four rights, each can be reserved for admins: send messages, add labels, edit group info (name, photo, description and, according to Signal's documentation, the disappearing-messages timer) and add members.²¹³⁴ While a right is not restricted, an ordinary member can use it, including changing the timer. Reserve them for admins (keyholders, and secretaries in the public group and the airlock group) and check them in each group; in the public group, only admins send messages. Removing a member stays reserved for admins, whatever you set: hence several reachable keyholders per group.²¹
4. No group link, no group QR code (the one exception: the public group, which holds nothing sensitive and whose link may circulate) → add each person by username, from a private conversation. A link that gets passed around escapes all control: anyone who has it can ask to join, and it can be relayed or found. The link is managed in the group link section: you turn it on, reset it or turn it off;⁵ an "require admin approval" option (keep it on wherever a link exists, except the public group) acts as a safety net, without replacing direct adding. If a link was created anyway, turn it off straight away, then reset it if in any doubt. Reserving "add members" for admins also limits who can create one: a member who does not see the feature has to go through an admin (to check in your group).
5. Group description → paste the short description (vital rules, non-violence disclaimer and legal reminder). Because disappearing messages delete pinned messages, the full charter is reviewed and agreed to in the airlock group before admission.
6. Second keyholder → add them and make them admin in Signal before anyone else.
7. Register → note the group ID and its keyholders.
8. Only then add the members.

A group that outgrows its size is split, it doesn't keep growing: the bigger a group, the more likely it contains a leak, and the more people a leak exposes. These sizes are common-sense benchmarks: everyone in the trusted group should at least recognise each other by sight, and really know each other in a sub-group. Airlock group too full: two meetings.

Create	When
A new family (new ID, with its trusted group and sub-groups)	The trusted group exceeds 25 people (50 at most) or its members no longer recognise each other by sight (split by neighbourhood or area); another city; a separate campaign; high-school students (with high-school keyholders); an unidentified leak (case B)
A liaison group (with its own ID, never that of one of the families)	Two or more families need to coordinate (see linking several families)
A sub-group	At least 3 to 5 people share a role and need to coordinate (medics, legal…)
A second sub-group for the same role, in the same family (MVT-CTY-4K9-Medic2)	The first exceeds 15 people, or two teams work on different ground
Nothing new	The need is one-off: name someone in the trusted group, or create a temporary group

• Match the timer to the announced meeting: it must cover the time left until the meeting, plus a margin (meeting in 6 days: 1 week; tomorrow: 1 day). Set it before posting the message: a new timer only applies to later messages,³ and every change shows up in the chat.
• A received message only starts disappearing once it has been read.³ On a seized phone, unread messages remain: short timers on action days. A few hours before the action, at the peak of organising, set the timer of the trusted group (and the sub-groups concerned) to a few hours, as short as possible (8 h, or 3 h as a custom time), and keep the meeting point on paper.
• Never in the description: names, addresses, meeting places, links to other groups, the list of sub-groups. No recognisable group photo.
• Keyholders don't go to an action with their keyholder phone when an arrest is possible: unlocked, it lets someone add members, read and change the group. Give the role to people who stay in the background, or remove it temporarily.
• Between keyholders, verify your safety numbers in person (QR code).⁶

Previous : Vetting · Next : Running the groups

Sources

Each note links to the source of the information. Most sources are in French. Laws change: check the date of the source and, if in doubt, ask a lawyer.

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1. Signal — Manage a group · AI-sourced on Oct 29, 2026 · awaiting human check ↩↩↩

2. Signal — Group chats · AI-sourced on Oct 29, 2026 · awaiting human check ↩↩↩

3. Signal — Set and manage disappearing messages · AI-sourced on Oct 29, 2026 · awaiting human check ↩↩↩↩↩↩

4. Signal — Label yourself (group member labels) · AI-sourced on Oct 29, 2026 · awaiting human check ↩

5. Signal — Group link or QR code · AI-sourced on Oct 29, 2026 · awaiting human check ↩

6. EFF Surveillance Self-Defense — How to use Signal · AI-sourced on Oct 28, 2026 · awaiting human check ↩