Introduction: privacy is useless if nobody can reach you
Most data protection advice starts from a comfortable assumption: your phone works, your plan is active, your accounts open, your address book is right there. On that basis, we can calmly discuss encryption, identity compartmentalisation or messages sent from a masked number.
Then comes an ordinary Tuesday. The phone falls into a puddle. The bag vanishes on a train. The carrier suffers a six-hour nationwide outage. A relative is hospitalised and you are 400 kilometres away with 4% battery. A SIM-swap fraud attempt strips you of your number for two days. These scenarios are not survivalist science fiction: they are statistically mundane incidents, and they share one formidable trait. Under pressure, we do the exact opposite of what we preach in calm times.
We borrow a stranger's phone. We connect to an open airport Wi-Fi. We hand our personal number to a service desk so they can "call us back". We hastily install an unknown app because it is the only one getting through. In three hours of stress, we hand out more identifying data than in three months of careful browsing.
This guide proposes the opposite: preparing an emergency communication plan in advance and in cold blood — a set of redundant means that keep you reachable and discreet, even when the main channel disappears. This is logistics, not paranoia.
Mapping your single points of failure
In security, a "single point of failure" is the element whose breakdown brings everything else down with it. For almost everyone in France, that point has a name: the smartphone.
Do the exercise honestly. This single object carries:
- your phone number, which has often become the primary identifier for your accounts;
- your address book, which you no longer know by heart;
- your second authentication factor, whether SMS or an authenticator app;
- your dematerialised payment methods;
- your travel tickets, your supporting documents, sometimes your home or car keys;
- all of your messaging apps.
One single incident — theft, breakage, dead battery, line suspension — and the whole stack collapses at once. The problem is not technical, it is architectural: you have concentrated everything. The answer is not to buy a sturdier device, but to spread things out.
The four families of scenarios
| Scenario | What goes down | What stays standing |
|---|---|---|
| Carrier outage | Calls, SMS, mobile data | Wi-Fi, third-party devices, landlines |
| Loss or theft of the device | Everything inside the device | Your accounts, if you can reach them elsewhere |
| Account compromise | Messaging, credentials | The telephone network, paper |
| Local incident (flood, fire, power cut) | Fixed network, electricity, sometimes mobile | Radio, batteries, another area's network |
Each family calls for a different response. A serious plan covers all four, not just the most spectacular one.
Step 1: rebuilding an offline memory
The first task is not technological. It is analogue redundancy.
The paper contact book
How many numbers do you know by heart? For most adults born after 1990, the answer hovers around one or two — often a childhood number. This is a real cognitive regression, thoroughly documented by research on "transactive memory": we delegate to machines what we used to memorise.
The countermeasure weighs a few grams. A pocket-sized hardcover notebook, containing:
- five to eight essential numbers (relatives, employer, GP, insurer, bank);
- a fallback postal address;
- emergency numbers: 15 (SAMU ambulance service), 17 (police), 18 (fire brigade), 112 (the European emergency number), 114 (the emergency number reachable by SMS and fax, intended in particular for deaf and hard-of-hearing people but available to anyone in a situation where speaking is impossible);
- 3117 (emergencies on public transport) and 116 000 (missing children).
Write this information without any context. A lost notebook that reads "Mum — Saint-X hospital — room 412" tells your life story; a list of first names and digits teaches almost nothing to whoever picks it up. That drafting detail is the heart of the exercise: preparing for reachability without compiling a file on yourself.
Duplicate documents
Photocopies of your ID card, health insurance card, driving licence and insurance policy: kept in a fireproof document folder or, failing that, with a trusted third party. The cloud is convenient, but it requires... access to an account, hence a second factor, hence the phone you have just lost. Paper asks for no password.
Step 2: separating the identifier from the channel
Here is where privacy protection meets resilience. An emergency plan forces you to answer an uncomfortable question: who should be able to reach you, and with how much information about you?
Normally, a single number serves every purpose: family, work, bank, delivery drivers, online shops, administrative forms. It is a universal identifier — and therefore a formidable cross-referencing key for anyone aggregating data. It is also, in the event of an incident, a single key whose loss blocks everything.
The three-circles principle
- Inner circle: five to ten people. They have your main line and a backup route (secondary line, dedicated email address, a relative acting as relay).
- Functional circle: employer, school, doctor, bank. They have your main line and an email address — never your backup route.
- Transactional circle: everyone else. Online shopping, one-off sign-ups, classified ads, single-day services. This circle should never touch your personal number.
It is precisely for this third circle that masked-sender SMS services find their legitimate place. Warning a tradesperson that you will be late, replying to an ad, confirming an appointment with someone you will never see again: none of these actions justifies handing over an identifier you will carry for fifteen years. The rule is simple and fits in one sentence: you don't use the same key for your house and for a swimming-pool locker.
The second line, kept plain
A prepaid SIM card from a carrier other than your own costs a few euros and covers two risks at once: the network outage of a single operator, and the unavailability of your main line after a theft or SIM fraud. In France, activating a prepaid SIM requires identifying the subscriber — so there is no total anonymity, and it is better to know that than to ignore it. That said, this line remains compartmentalised: it is linked to none of your accounts, it appears in no commercial database, and it serves emergencies only.
A basic keypad mobile phone, able to last a week on a single charge, usefully rounds out the setup. No account, no synchronisation, no apps: calls and texts only. It is the only device that will still be working on day four of a power cut.
Step 3: securing access to your accounts without the phone
This is the most common and most underestimated scenario: you have not lost your data, you have lost the key that opens it.
Breaking free from SMS dependency
SMS authentication remains the most widespread second factor. It is better than nothing, but it depends on your line being available — exactly what disappears in the event of theft, SIM fraud or a stay abroad. ANSSI (the French national cybersecurity agency) has recommended for several years favouring second factors that are independent of the mobile network.
Two concrete complements:
- Backup codes. Almost every major service offers them: a list of single-use codes, generated once, ready to print. They work without a network, without a battery, without an app. Store them with your paper documents, not in a note on your phone.
- A physical security key. A small keyring-sized device you plug in or tap against your device, replacing the code sent by SMS. Get two: one on you, one at a relative's home or in a locked drawer. A FIDO2 security key lost without a duplicate is a door closed for good.
The password manager, but with an emergency exit
A password manager is indispensable — provided it does not become a single point of failure in its own right. Make sure you can answer this question: if my phone and my computer disappeared today, how would I open my vault tomorrow? If there is no answer, the vault is a trap. Write the master password down on paper, sealed, kept with a trusted third party or in a home safe.
Step 4: hardware autonomy
A communication plan that assumes a power socket is not a plan.
Energy
A high-capacity power bank (10,000 mAh minimum) kept charged at 60–80% provides three to four full smartphone recharges. Check it twice a year: a battery forgotten in a drawer for eighteen months is often flat or swollen. For households exposed to outages — rural areas, windy regions, the coast — a foldable hiking solar panel saves you from having to choose between lighting and communicating.
Information
During major weather events, mobile networks become saturated before they go down. Radio, on the other hand, keeps going. The frequencies of France Bleu and France Inter are part of the public alert system, and prefectures broadcast their instructions through this channel. A hand-crank FM radio with a built-in lamp is the most rustic and most reliable item on the list. It collects nothing, never updates and asks for no account.
The grab bag
Gather everything — notebook, backup codes, second SIM, power bank, charger, a little cash — into a single pouch, stored somewhere everyone in your household knows. In a stressful situation, having to search is already a failure.
Step 5: writing the procedures before you need them
Equipment is useless without a scenario. Three short protocols are enough, fitting on a single page.
The "rallying point" protocol
Agree with your family on a place and a time to meet up, plus a relay contact living in another region. The logic is well established: during a local incident, outbound communications to the outside world often get through better than communications within the saturated area. Everyone contacts the relay, who centralises and redistributes the information.
The "minimal message" protocol
In an emergency, a text message has a better chance of getting through than a call: it weighs a few dozen bytes and the network queues it until it goes through. Format it in advance:
STATUS: ok / lightly injured / need help — LOCATION: [town, landmark] — NEEDS: [none / water / transport] — NEXT CONTACT: [time]
Four fields, no storytelling. A short message gets through, a long one fails.
The "lost device" protocol
In order, without thinking:
- Have the line suspended by your carrier (the number is in your paper notebook, not in the stolen phone).
- Report the loss or theft and, if necessary, have the device blocked via its IMEI number, noted down in advance.
- Revoke active sessions on sensitive accounts from another device.
- Warn your inner circle — from the second line — that any message received from your usual number may be fraudulent.
That fourth point is far too often forgotten. A stolen phone is first and foremost used to message your contacts while impersonating you. Getting ahead of it cuts the scam off at the root.
What this plan really protects
You might think this is survivalism. It is something else. An emergency communication plan is an act of data protection, for one simple reason: panic is the leading cause of voluntary personal information leaks.
The person who has prepared a list of numbers does not ask a stranger to let them open their inbox on a borrowed phone. The one who has a compartmentalised second line does not hand their main identifier to the first service desk that asks. The one who has printed backup codes does not fall back on "recovery via secret question", which exposes their date of birth and their mother's maiden name.
Confidentiality is not a wall, it is a set of options available at the right moment. Multiplying channels means guaranteeing yourself the right to choose which one to use — including the one that does not say your name. As the CNIL regularly points out in its digital hygiene recommendations, data minimisation starts with a common-sense question: do I really need to give this information to this party, right now?
One quiet Sunday, a notebook, a few euros' worth of equipment and an hour of thought are enough to make sure the answer stays "no" even on the day when everything goes wrong.
Recap: the checklist
- Paper notebook with 5 to 8 essential numbers and the emergency numbers (112, 114)
- Backup codes for critical accounts, printed and stored offline
- A second line, from a different carrier, kept separate from your accounts
- A physical security key, plus a duplicate stored elsewhere
- Power bank checked twice a year
- Self-powered radio and lamp
- Three written protocols: rallying point, minimal message, lost device
- A masked-sender channel for everything that belongs to the transactional circle
