Unlock or decrypt an APFS drive
One of the main features of macOS High Sierra is the new file system of APFS. Apple File System is a new, modern file system optimized for working with Flash / SSD drives. It includes the functionality of strong encryption, copy-on-write, space sharing, cloning files and folders, creating snapshots.
As part of the working with the Apple File System (APFS) volumes, it may be necessary to decrypt a boot drive using APFS’s native encryption in order to fix a problem.
This article shows you how to decrypt an encrypted APFS boot disk from the command line. For this purpose it is not possible:
1. Identify the relevant encrypted APFS volume.
2. Unlock the encrypted APFS volume
3. Decrypt the encrypted APFS volume.
More information you can find in this article.