FileVault Encryption to New APFS Volume

With a T2 or Apple Silicon Mac, the internal SSD is always hardware encrypted since that is how those systems work. You must authenticate with the security enclave on the computer in order to be able to access anything on the Mac since the security enclave controls access to the encryption keys, otherwise the hardware encryption would mean nothing if the computer unlocked the encryption for everyone. When you put a 2018+ Mac into Target Disk Mode, you will be prompted to authenticate with the security enclave of the Mac in Target Disk Mode in order to unlock the encrypted SSD.

With a T2 or Apple Silicon Mac, enabling Filevault just adds an extra password to the process according to Apple (sorry I cannot find the Apple article which has a one line reference to it and Apple does not explain it any further).

FYI, make sure to always have frequent and regular backups of the computer since there are a lot of ways of losing your data on these systems.

FileVault really isn’t the encryption process. It is the “magic” that decrypts and logs in using the same login credentials. You can encrypt volumes in a container separately. If you add a volume and encrypt it, I believe it will be a separate password (which can be stored in your login keychain).

Is it a T2 or Apple silicon Mac. Those are always encrypted, but automatically decrypted if you don’t turn on FileVault.

I’m not sure in what conditions it decrypts automatically. This Macworld article seems to indicate it might auto-decrypt at power up, so you probably need to encrypt the volume. https://www.macworld.com/article/234494/how-filevault-and-the-t2-security-chip-work-together-in-newer-macs.html

I haven’t tried anything like that.

Just realized that the "Recovery" APFS volume is part of the main Container and is not encrypted by Filevault (at least with Big Sur on an Intel Mac). The recovery volume cannot be encrypted since the system needs to boot from it without any credentials (at least for the 2017 and earlier Intel models).