Can any data be recovered without a password/PIN?

Question

If someone doesn't know the password required on boot, is there a way to access the data on the device?

It should be encrypted, but I read about Samsung adding something called Maintenance Mode where you can prevent repair techs from accessing your data. From this I assume it's otherwise possible for them to access your data even if they don't know the password. And if a repair tech can access the data, then a phone thief can as well.

If this data can't be accessed, then what's the point of Maintenance Mode and similar features on other brands?

Answer 1

Here's what Samsung explained about Maintenance Mode and how it helps:

Maintenance Mode is a way of creating a separate user account when you hand in your device to be repaired so they can operate core functions without being able to access to any of your private information. All the user needs to do is select Maintenance Mode in the “Battery and device care” menu within “Settings” and reboot their smartphone. As soon as it’s rebooted, all their personal information including their photos, documents and messages will be restricted.2

Once Maintenance Mode is switched on, the person who was entrusted with the device won’t be able to retrieve user-installed apps either. Data or accounts generated when using Maintenance Mode are automatically deleted as soon as the owner exits Maintenance Mode. They will be able to download apps on Galaxy Store, but those will be automatically deleted along with any data or accounts created as soon as the owner exits Maintenance Mode.

This seems to be like Guest user account which the user can create and has been offered in Android devices for quite a long time. A user account in Android restricts one user from accessing private data of another user. This private data is encrypted for the user accounts. Guest user is configured to automatically dispose of all the changes a user has made while using the guest account, once the device is switched to another user account.

A problem with multiuser setup in Android devices is that upon reboot Android requires the primary user (owner) to provide their credentials, even if only a secondary or a guest user want to use the device. If Samsung has not solved this problem with their Maintenance mode than it might prove to be annoying for both the users and technicians alike.

To summarize, enabling Maintenance mode and giving your device to a stranger would not enable them to access your private data since it is encrypted and they would not have your credentials to unlock your lock screen. Make sure to use a slightly complicated credential before you hand over your device. Brute forcing is harder on Android since the OS progressively restricts these attempts. By using complicated credential the other person would not be able to make way with easier guesses such as 'password', '1212', '12345', etc.