6 min read
What WhatsApp's encrypted backup actually protects
Encrypted backup guards one specific thing: the copy of your chats in the cloud. Here is what it covers, what it does not, and the trade you are making.
By WaChat
WhatsApp has been end-to-end encrypted for years, which leads a lot of people to assume everything about it is already covered. Then a settings screen appears offering to turn on end-to-end encryption for backups, and the obvious question is what exactly was unencrypted until now.
The answer is worth understanding, because this particular setting comes with a real and permanent trade-off.
Two different encryptions
Messages in transit have been end-to-end encrypted for a long time. A message leaves your phone encrypted and is decrypted on the recipient's phone. Nobody in between — not the network, not WhatsApp — can read it.
Backups at rest were a separate matter. When your phone uploaded a nightly backup to Google Drive or iCloud, that copy sat under your cloud provider's protection rather than under a key that only you hold. It was not exposed to the world, but the security model was fundamentally different from the one protecting the messages themselves.
End-to-end encrypted backup closes that gap. The backup is encrypted on your phone, before it is uploaded, with a key that WhatsApp does not keep.
The two ways to hold the key
When you turn it on, WhatsApp asks how you want to hold the key, and the choice matters:
A 64-digit key. WhatsApp generates a 256-bit key, shows it to you once as sixty-four hexadecimal digits, and keeps no copy. Nothing about it is stored on any server. It is the strongest option and the least forgiving: lose those digits and the backup is permanently unreadable.
A password. You choose a password, and the key is derived from it and kept in a hardware key vault that unlocks only with that password and strictly limits guessing attempts. More convenient, because you can recover a backup by remembering something. Slightly more surface area, because the key material exists somewhere other than in your head.
A passkey. Newer, and the default WhatsApp now offers on many devices. It ties the backup to the biometrics of your device. Very convenient for restoring to a new phone, and worth knowing about one consequence: a passkey lives inside your device's secure hardware and cannot be exported, so nothing outside WhatsApp — including WaChat — can use it to open the backup. If you want to be able to read your own backup with anything else, choose the 64-digit key instead.
There is a longer piece on the 64-digit key specifically: the 64-digit key, explained.
What it protects against
| Threat | Protected? |
|---|---|
| Someone gains access to your Google or Apple account | Yes — the backup is unreadable without your key |
| Your cloud provider's staff or systems | Yes |
| A legal demand served on the cloud provider | Yes — they hold bytes they cannot decrypt |
Someone gets the crypt15 file off your phone | Yes, provided they do not also have your key |
| Someone unlocks your phone | No — WhatsApp is open on it |
| The other person in the conversation keeps their copy | No |
| Screenshots, forwards, or an export you made | No |
| You losing the key | No — and this is the risk that actually materialises |
The pattern is clear once you see it: encrypted backup protects the copy in the cloud. It does nothing about copies that exist anywhere else, and there are always copies somewhere else. Every conversation has at least two participants and at least two phones.
The trade you are making
There is no recovery path. That is not a limitation waiting to be improved; it is the entire mechanism. If WhatsApp could restore your backup for you, then WhatsApp could read your backup, and it would not be end-to-end encrypted.
So turning this on moves a real risk from one place to another. Before: your backup was readable by a provider you trust to varying degrees. After: your backup is readable by nobody except you, and the odds of you losing access go up.
That trade is usually worth taking. But it only works if you treat the key as something you genuinely keep — a password manager entry, or written on paper somewhere you will find it in ten years. A screenshot in your photo library is not that: photo libraries sync to the cloud, get shared into albums, and surface in "on this day" widgets while somebody else is looking at your screen.
Turning it on, correctly
The order matters, and getting it wrong is the single most common problem people hit afterwards.
- Settings → Chats → Chat backup → End-to-end encrypted backup.
- Tap Turn on. If it is already on with a passkey and you want digits, turn it off first, then on again.
- Choose "Use 64-digit encryption key instead".
- Save the key somewhere durable. WhatsApp shows it once.
- Run a new backup. Go back to Chat backup and tap Back up, and wait for it to finish.
Step 5 is the one people skip. Generating a key does not re-encrypt the backup that already exists — yesterday's file is still sealed with yesterday's key. Until you run a fresh backup, the key you just saved and the file on your phone do not match, and any attempt to open it reports a wrong key. The wrong key article walks through the other causes.
Each time you turn encrypted backup off and on again, WhatsApp generates a new key. Old backup files stay locked to the old one. If you archive old backups, archive the matching key with them, labelled.
What this means for reading your own history
Encrypted backup is the reason you can read your own archive at all — and the reason nobody else can.
The local file on Android, msgstore.db.crypt15, is the same encrypted database, sealed with the same key. Because you hold that key, you can decrypt it yourself and get every message in every chat, with none of the caps that apply to exporting a chat. That is what WaChat does: the decryption runs in a background worker in your browser, or inside the Android app, using your key. The key is not sent anywhere, not written to a log, and not included in crash reports. If you would rather not store it at all, paste it each time and it lives only for that session.
The same property makes one rule absolute: never send your key to anyone. Not to support, not to us, not to a service offering to help. The file alone is useless to an attacker and the key alone is useless too — the whole security model rests on those two never travelling together. Anyone asking for your key is asking for the one thing that makes your backup readable.
Where to go from here
End-to-end encrypted backup makes the cloud copy of your chats readable by you alone. It does not protect your phone, the other person's phone, or anything you export — and it makes losing the key permanent.
Turn it on, choose the 64-digit key, run a fresh backup, and store the key somewhere you would store a passport.
- Step-by-step, with the passkey caveat: getting your 64-digit encryption key.
- Exactly what we can and cannot see: privacy: what we can and cannot see.
- Using your own key to read your own history: the import guide.