pmt-ehd(8)

Name

pmt-ehd - create an encrypted disk image

Syntax

pmt-ehd [-DFx] [-c fscipher] [-h hash] [-k fscipher_keybits] [-t fstype] [-H header_path] -f container_path -s size_in_mb

Options

Mandatory options that are absent are inquired interactively, and pmt-ehd will exit if stdin is not a terminal.

-D  Turn on debugging strings.

-F  Force operation that would otherwise ask for interactive confirmation. Multiple -F can be specified to apply more force.

-c cipher
    The cipher to be used for the filesystem. This can take any value that cryptsetup(8) recognizes, usually in the form of "cipher-mode[-extras]". Recommended are aes-cbc-essiv:sha256 (this is the default) or aes-xts-essiv:sha256.

-f path
    Store the new disk image at path. If the file already exists, pmt-ehd will prompt before overwriting unless -F is given. If path refers to a symlink, pmt-ehd will act even more cautious.

-H path
    Store a detached (separate) metadata file with a new LUKS header at path. If the file already exists, pmt-ehd will prompt before overwriting unless -F is given. If path refers to a symlink, pmt-ehd will act even more cautious. The default is to not use a detached header. Correlates with the `cryptsetup --header` option.

-h hash
    Message digest/hash used for key derivation in the PBKDF2 stage. The default is sha512.

-i cipher
    (This option had been removed in pam_mount/pmt_ehd 2.11.)

-k keybits
    The keysize for the cipher specified with -c. Some ciphers support multiple keysizes, AES for example is available with at least the keysizes 192 and 256. Defaults to 256 (to match aes-cbc-essiv). Note that XTS uses two keys, but drawn from the same key material, so aes-cbc-256 is equivalent to aes-xts-512, and aes-cbc-128 is to aes-xts-256.

-p path
    (This option had been removed in pam_mount/pmt_ehd 2.11.)

-s size
    The initial size of the encrypted filesystem, in megabytes. This option is ignored when the filesystem is created on a block device.

-t fstype
    Filesystem to use for the encrypted filesystem. Defaults to xfs.

-u user
    Give the container and fskey files to user (because the program is usually runs as root, and the files would otherwise retain root ownership).

-x  Do not initialize the container with random bytes. This may impact secrecy.

  Description

pmt-ehd can be used to create a new encrypted container, and replaces the previous mkehd script as well as any HOWTOs that explain how to do it manually. Without any arguments, pmt-ehd will interactively ask for all missing parameters. To create a container with a size of 256 MB, use:

pmt-ehd -f /home/user.cont -s 256