Verify Time Machine Encryption from the Command-Line? Is it possible to verify whether a given Time Machine volume (for example, returned by tmutil machinedirectory) has encryption turned on?  This is for regulatory compliance, so it needs to be fully scriptable.
If you know the UUID before you mount the disk you can use:

diskutil coreStorage list XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX


This will give the following output.

Logical Volume Family XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
----------------------------------------------------------
Encryption Status:       Unlocked
Encryption Type:         AES-XTS
Conversion Status:       Complete
Conversion Direction:    -none-
Has Encrypted Extents:   Yes
Fully Secure:            Yes
Passphrase Required:     Yes


If you know the mountpoint of the disk, you can get the UUID by the following command.

diskutil info /MOUNTPOINT | grep UUID | awk '{print $3}'


And if you do not know the mountpoint you can always run

diskutil coreStorage list


A MacMini with two encrypted drives (Macintosh SSD &amp; Backup Mini) will give the following output.

CoreStorage logical volume groups (2 found)
|
+-- Logical Volume Group XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
|   =========================================================
|   Name:         Macintosh SSD
|   Status:       Online
|   Size:         250140434432 B (250.1 GB)
|   Free Space:   16777216 B (16.8 MB)
|   |
|   +-&lt; Physical Volume XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
|   |   ----------------------------------------------------
|   |   Index:    0
|   |   Disk:     disk0s2
|   |   Status:   Online
|   |   Size:     250140434432 B (250.1 GB)
|   |
|   +-&gt; Logical Volume Family XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
|       ----------------------------------------------------------
|       Encryption Status:       Unlocked
|       Encryption Type:         AES-XTS
|       Conversion Status:       Complete
|       Conversion Direction:    -none-
|       Has Encrypted Extents:   Yes
|       Fully Secure:            Yes
|       Passphrase Required:     Yes
|       |
|       +-&gt; Logical Volume XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
|           ---------------------------------------------------
|           Disk:               disk2
|           Status:             Online
|           Size (Total):       249804886016 B (249.8 GB)
|           Size (Converted):   -none-
|           Revertible:         Yes (unlock and decryption required)
|           LV Name:            Macintosh SSD
|           Volume Name:        Macintosh SSD
|           Content Hint:       Apple_HFS
|
+-- Logical Volume Group XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
    =========================================================
    Name:         Backup Mini
    Status:       Online
    Size:         999860912128 B (999.9 GB)
    Free Space:   0 B (0 B)
    |
    +-&lt; Physical Volume XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk3s2
    |   Status:   Online
    |   Size:     999860912128 B (999.9 GB)
    |
    +-&gt; Logical Volume Family XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
        ----------------------------------------------------------
        Encryption Status:       Unlocked
        Encryption Type:         AES-XTS
        Conversion Status:       Complete
        Conversion Direction:    -none-
        Has Encrypted Extents:   Yes
        Fully Secure:            Yes
        Passphrase Required:     Yes
        |
        +-&gt; Logical Volume XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
            ---------------------------------------------------
            Disk:               disk5
            Status:             Online
            Size (Total):       999542136832 B (999.5 GB)
            Size (Converted):   -none-
            Revertible:         No
            LV Name:            Backup Mini
            Volume Name:        Backup Mini
            Content Hint:       Apple_HFS