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How to read an encrypted iPhone backup on Windows

Published 29 July 2026 · Krzysztof Kowalski

An encrypted iPhone backup is readable on Windows if you have the password, and unreadable by anyone if you do not. Ticking “Encrypt local backup” in Apple’s software does not add a lock on top of a normal backup: it changes the contents of the folder, encrypts the index that lists what is inside, and gives you more data than an unencrypted backup would have contained. This page explains what happens in that folder, because the decision is usually made in one second at the start and regretted much later.

One warning before the detail. Everything below is about opening your own backup with your own password. There is no technique here for getting into a backup whose password you do not have, because there is not one to describe.

What actually changes in the folder when you encrypt?

The layout does not change. You still get a device folder full of files with forty character names, plus Manifest.db, Manifest.plist, Info.plist and Status.plist.

Three things are different:

  1. Manifest.plist gains a flag and a keybag. The flag is IsEncrypted, and it is how any program knows to ask for a password rather than trying to open a database and failing. Alongside it sits a blob called BackupKeyBag, which holds the key material.
  2. Manifest.db is encrypted. That is the index of everything in the backup, so until the password is supplied you cannot even see what the backup contains, let alone read it.
  3. Every file is encrypted with its own key. Not one key for the backup. One per file, each wrapped so that it can only be unwrapped through the keybag.

Info.plist stays readable. That is why a tool can tell you which phone and which iOS version a backup came from before you have typed anything.

How does the password become the keys?

The keybag is a sequence of records, each one a four character tag, a four byte big-endian length, and a value. The header records carry the backup salt and an iteration count. Backups from iOS 10.2 onwards carry a second salt and iteration count as well, because Apple added an extra hardening round at that point.

The password becomes a key in one or two passes, depending on the age of the backup:

  • iOS 10.2 and later: PBKDF2-HMAC-SHA256 over the password with the newer salt and iteration count, producing 32 bytes, and then PBKDF2-HMAC-SHA1 over that result with the original salt and iteration count, producing the final 32 byte key.
  • Older backups: the SHA1 round alone.

Then, after the header, the keybag lists protection classes. Each entry records the class number, a bitmask saying how its key is wrapped, and the wrapped key itself. Entries whose bitmask says “wrapped by the passcode” are the ones the derived key opens, using AES Key Wrap as published in RFC 3394. That algorithm has its own integrity check built in, which is a detail with a practical consequence: a wrong password does not produce garbled data, it produces a clean failure. You find out immediately rather than after exporting a thousand corrupt messages.

Per file, the same shape again: Manifest.db stores a small blob holding the file’s protection class and its own wrapped key, that key is unwrapped with the class key, and the file is decrypted with AES-256-CBC using a zero initialisation vector. The ciphertext is padded up to the block size, so the real length is taken from the metadata and the tail discarded.

None of this is exotic. It is standard, well documented cryptography, assembled carefully.

Why does it take a few seconds to unlock?

Real backups use around ten million PBKDF2 iterations. On a normal laptop that is seconds of solid CPU work for a single password attempt.

That delay is deliberate, and it is the whole security argument. Ten million iterations is barely noticeable when you type the right password once. It is ruinous when you want to try a hundred million candidates, which is the difference between a backup that is protected and one that merely looks protected.

Two practical consequences. A program that appears to freeze for a moment after you type the password is doing the work rather than misbehaving. And “just brute force it” is not advice, it is a way of saying no slowly.

What does an encrypted backup contain that an unencrypted one does not?

Saved passwords, Health data and Wi-Fi settings, none of which Apple puts in an unencrypted backup at all. This is the part most people have never been told, and it is the actual reason to encrypt rather than a security lecture.

So the choice is not “the same backup, locked or unlocked”. It is a smaller backup or a more complete one, and the more complete one happens to be the protected one.

An unencrypted backup is every message you have ever sent, sitting in a readable folder on a PC, in a form that anyone with access to the machine can copy.

If you are preparing a custody case or an employment dispute, that folder is not a temporary thing. You will be keeping it for months, because it is the source your exported document came from and the thing that lets anyone repeat the export and get the same messages. Keeping it encrypted is the difference between one artefact somebody has to defeat and one they only have to find.

Set a password you will still have in a year and write it somewhere that is not the same computer.

Can a lost backup password be recovered?

There is no escrow copy. No vendor override. No support process, at Apple or anywhere else, that opens an encrypted backup without its password. There is no weakness to exploit and no “professional recovery service” that has one, whatever their advertising says.

If the phone still exists and is working, the way out is not to attack the old backup. It is to remove the backup password on the device and make a new backup. The switch Apple provides for that is Settings, General, Transfer or Reset iPhone, Reset, Reset All Settings. Know what it does before tapping it: it removes the backup password, and it also resets the phone’s system settings, including saved Wi-Fi networks, wallpaper and privacy choices. Messages, photos and apps stay where they are. If the phone is gone and the password with it, the backup is a folder of noise, permanently.

How ChatExport handles it

It asks for the password when it needs it, uses it on your machine, and forgets it. The password is never written to disk and never sent anywhere, because there is nowhere for it to be sent: the program has no server and makes no network requests. Only the files actually needed for the export are decrypted, and they are cleared when the app closes. Type it wrong and it simply asks again.

The backup list, showing an iPhone backup found on this PC with its date, how long ago it was made and the iOS version

That is also the reason the app can be honest about the limit. It cannot help you with a password you do not have, and any program that claims otherwise is either wrong or describing something else.