I tried the following

sudo cryptsetup luksChangekey /dev/nvme0n1p3 < new passphrase > 

It then asks for the Sudo password, then asks for the old passphrase, but then it prints this error message

Failed to open key file.

what went wrong ?

Edit: turns out using GNOME Disks is way more straightforward.. 😅, thank you all

  • booooop [any]
    ·
    6 months ago

    What is the output if you run sudo cryptsetup --verbose open --test-passphrase /dev/nvme0n1p3?

    • 乇ㄥ乇¢ㄒ尺ㄖ@infosec.pub
      hexagon
      ·
      6 months ago

      It asks for the sudo password, then it prints

      No usable token is available.
      

      Then it asks : Enter passphrase for /dev/nvme0n1p3:

      After entering my old passphrase it prints:

      Key slot 0 unlocked
      Command Successful.
      
      • booooop [any]
        ·
        6 months ago

        Alright so no permission issue, what if you run the changekey command in a separate bash subprocess? sudo bash -c '($your-changekey-command-here)'

        • 乇ㄥ乇¢ㄒ尺ㄖ@infosec.pub
          hexagon
          ·
          6 months ago

          Is it like the same first "cryptsetup luksChangekey..." But inside parentheses ? Im sure I'm getting the syntax wrong.. It prints

          bash: line 1: -luksChangekey: command not found