Changing encrypted volume passphrases on macOSEdit

Created , updated

I backup to multiple external volumes and occasionally have cause to change the passphrases, but can never remember how to do it because Apple makes it ridiculously obtuse.

Update: At least as of macOS "High Sierra" 10.13.6, Disk Utility has gained (regained?) the ability to change passphrases on CoreStorage volumes, as well as gaining the ability to change passphrases on APFS volumes.

Encrypted .dmg file

hdiutil chpass path/to/image.dmg

Encrypted APFS volume

You can do this using recent versions of Disk Utility and selecting the inner volume, then selecting "Change Password…" from the "File" menu.

Encrypted CoreStorage volume

You can do this using recent versions of Disk Utility and selecting the inner volume, then selecting "Change Password…" from the "File" menu.

Command-line alternative

diskutil coreStorage changeVolumePassphrase $UUID

Get the $UUID by mounting the volume and inspecting the output of diskutil cs list. You’re looking for the "Logical Volume" UUID at the bottom of the output:

+-- Logical Volume Group 12345678
    =========================================================
    Name:         Nemesio
    Status:       Online
    Size:         3679412224 B (3.7 GB)
    Free Space:   4096 B (4.1 KB)
    |
    +-< Physical Volume 12345678
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk2s2
    |   Status:   Online
    |   Size:     3679412224 B (3.7 GB)
    |
    +-> Logical Volume Family 12345678
        ----------------------------------------------------------
        Encryption Type:         AES-XTS
        Encryption Status:       Unlocked
        Conversion Status:       Converting (forward)
        High Level Queries:      Not Fully Secure
        |                        Passphrase Required
        |                        Accepts New Users
        |                        Has Visible Users
        |                        Has Volume Key
        |
        +-> Logical Volume 12345678
            ---------------------------------------------------
            Disk:                  disk4
            Status:                Online
            Size (Total):          3343863808 B (3.3 GB)
            Conversion Progress:   60%
            Revertible:            Yes (unlock and decryption required)
            LV Name:               Nemesio
            Volume Name:           Nemesio
            Content Hint:          Apple_HFSX