Restoring the backup of an encrypted phone I had an LG G2, running LineageOS 7.1 with enabled encryption. I took regular backups using TWRP 3 (which can deal with encryption).

The phone broke. I now want to restore the backup using TWRP on a new LG G2. 

How can I restore the backup from the old phone using encryption onto the new phone (no encryption yet)? 

I tried to restore the backup as-is and it doesn't boot (black screen). Anything special that I need to do before restoring?

Should I first encrypt the new phone and then restore the backup? Or do I need to strip the encryption from the backup somehow before restoring it?
As it turns out, TWRP/nandroid backups aren't encrypted. The encryption layer sits lower at the level of the device.

You can therefore restore the backup on a new device like any other backup simply by using the restore function in TWRP. You have to re-enable encryption afterwards, of course.

This also means that backup data is not encrypted and therefore must be protected in storage. I've never read this anywhere; be aware of the security implications.

Edit: The reason for the above mentioned boot problem was unrelated to the backup. I had the wrong bootstack on the new phone and first needed to upgrade to the most recent stock rom.