End-to-end encryption, explained for families

"End-to-end encrypted" is printed on a lot of boxes now. Here's what it means, what it costs you, and why the cost is the point. It's written for the family member who never volunteered to be the IT department.

Two kinds of locked

Almost every service you use encrypts your data. The real question is who holds the key.

Most services work like a bank locker where the bank keeps a master key. Your files are locked away from outsiders, but the company can open them: to show you your data on a new phone, to reset your password, and sometimes to scan your files. You're trusting a promise that they could look but won't.

End-to-end encryption works differently. Your data is locked on your own device, before it's sent, with keys that only your devices hold. The company stores sealed boxes it cannot open. Not "chooses not to", but cannot, in the same way your neighbour can't read a letter that was never in their house. When we say we can't see your documents, that's how it works, not a policy.

What it protects your family from

Quite a lot:

• A break-in at the company. Someone who steals the server's contents gets sealed boxes. It's a bad day for the company, but your documents still can't be read by anyone outside your family.
• The company's own staff. No employee can browse your files, whether they're curious, tricked or holding a grudge.
• Pressure on the company. A company that can't read your data can't be talked, tricked or forced into handing over what's inside. It can only hand over the sealed boxes.

What it doesn't protect you from

This list matters too. End-to-end encryption does nothing if your own device is compromised. If someone can unlock your phone, they see what you see. And some information has to stay readable for the service to work at all: that your account exists, roughly how much you store, and the titles and dates that make search and reminders work. Any company that says otherwise is rounding up. We publish our exact list on the security page.

The part nobody advertises: getting back in

This is the consequence that matters most for a family, and the one glossy explanations skip.

"Forgot password" links work because the company can get into your data and attach it to a new password. That's the master key at work. A company that truly can't read your data also can't reset your way back in. It's the same ability.

So with end-to-end encryption, getting back in has to be arranged in advance, by you. In Vault For Us there are two ways. Your Recovery Kit is a code made on your own device and written on paper, kept wherever you'd keep a spare house key. It can always unlock your data and let you set a new master password. And your family helps: each person signs in on their own devices, so one forgotten password is an inconvenience rather than a disaster, and a family member who can still sign in can approve your way back in.

What doesn't exist, ever, is a support ticket that gets your data back without the code. We can't offer that, because being able to offer it is exactly what we built the product not to do.

Is it worth it?

It depends on what's being stored. For a music playlist, convenience wins, so take the password reset. For passports, medical records, property papers and the family's passwords, the things that would do the most harm in the wrong hands, we think the answer is different. Keeping one piece of paper safe is a fair price for knowing nobody else can ever read them.

What we'd ask of any company, us included: tell people which kind of locked they're getting. Both can be reasonable choices. Only one of them should call itself end-to-end encrypted.

The longer version, including what we can and can't see, is on our security page.