Ubuntu Manpage: cryptsetup-tcryptDump - dump the header information of a TCRYPT (TrueCrypt or VeraCrypt compatible)

Provided by: cryptsetup-bin_2.8.0-1ubuntu2_amd64

NAME

       cryptsetup-tcryptDump - dump the header information of a TCRYPT (TrueCrypt or VeraCrypt compatible)
       device

SYNOPSIS

       cryptsetup tcryptDump [<options>] <device>

DESCRIPTION

       Dump the header information of a TCRYPT (TrueCrypt or VeraCrypt compatible) device.

       If the --dump-volume-key option is used, the TCRYPT device volume key is dumped instead of TCRYPT header
       info. Beware that the volume key (or concatenated volume keys if cipher chain is used) can be used to
       decrypt the data stored in the TCRYPT container without a passphrase. This means that if the volume key
       is compromised, the whole device has to be erased to prevent further access. Use this option carefully.

       <options> can be [--dump-volume-key, --key-file, --tcrypt-hidden, --tcrypt-system, --tcrypt-backup,
       --veracrypt (ignored), --disable-veracrypt, --veracrypt-pim, --veracrypt-query-pim, --cipher, --hash,
       --header, --verify-passphrase, --timeout].

       The keyfile parameter allows a combination of file content with the passphrase and can be repeated.

OPTIONS

--batch-mode, -q
Suppresses all confirmation questions. Use with care!

If the --verify-passphrase option is not specified, this option also switches off the passphrase
verification.

--cipher, -c <cipher-spec>
Set the cipher specification string for plain device type.

For tcrypt device type it restricts checked cipher chains when looking for header.

--debug or --debug-json
Run in debug mode with full diagnostic logs. Debug output lines are always prefixed by #.

If --debug-json is used, additional LUKS2 JSON data structures are printed.

--disable-veracrypt
This option can be used to disable VeraCrypt compatible mode (only TrueCrypt devices are recognized).
Only for TCRYPT extension. See TCRYPT section in cryptsetup(8) for more info.

--dump-volume-key, --dump-master-key (OBSOLETE alias)
Print the volume key in the displayed information. Use with care, as the volume key can be used to
bypass the passphrases, see also option --volume-key-file.

--hash, -h <hash-spec>
Specifies the passphrase hash. Applies to plain and loopaes device types only.

For tcrypt device type, it restricts checked PBKDF2 variants when looking for header.

--header <device or file storing the LUKS header>
Use a detached (separated) metadata device or file where the LUKS header is stored. This option
allows one to store ciphertext and LUKS header on different devices.

For commands that change the LUKS header (e.g. luksAddKey), specify the device or file with the LUKS
header directly as the LUKS device.

--help, -?
Show help text and default parameters.

--key-file, -d name
Read the passphrase from file.

If the name given is "-", then the passphrase will be read from stdin. In this case, reading will not
stop at newline characters.

See section NOTES ON PASSPHRASE PROCESSING in cryptsetup(8) for more information.

--tcrypt-backup, --tcrypt-hidden, --tcrypt-system
Specify which TrueCrypt on-disk header will be used to open the device. See TCRYPT section in
cryptsetup(8) for more info.

Using a system-encrypted device with the --tcrypt-system option requires specific settings to work as
expected.

TrueCrypt/VeraCrypt supports full system encryption (only a partition table is not encrypted) or
system partition encryption (only a system partition is encrypted). The metadata header then contains
the offset and size of the encrypted area. Cryptsetup needs to know the specific partition offset to
calculate encryption parameters. To properly map a partition, you must specify a real partition
device so cryptsetup can calculate this offset.

While you can use a full device as a parameter (/dev/sdb), always prefer to specify the partition you
want to map (/dev/sdb1) as only system partition mode can be detected this way.

For mapping images (stored in a file), you can use the additional --header option with the real
partition device. If the --header is used (and it is different from the data image), cryptsetup
expects that the data image contains a snapshot of the data partition only.

If --header is not used (or points to the same image), cryptsetup expects that the image contains a
full disk (including the partition table). This can map a full encrypted area not directly mountable
as a filesystem. Please prefer creating a loop device with partitions (losetup -P, see losetup(8) man
page) and use a real partition (/dev/loopXp1) as the device parameter.

--timeout, -t <number of seconds>
The number of seconds to wait before timeout on passphrase input via terminal. It is relevant every
time a passphrase is asked. It has no effect if used in conjunction with --key-file.

This option is useful when the system should not stall if the user does not input a passphrase, e.g.
during boot. The default is a value of 0 seconds, which means to wait forever.

--usage
Show short option help.

--veracrypt
This option is ignored as VeraCrypt compatible mode is supported by default.

--veracrypt-pim, --veracrypt-query-pim
Use a custom Personal Iteration Multiplier (PIM) for VeraCrypt device. See TCRYPT section in
cryptsetup(8) for more info.

--verify-passphrase, -y
When interactively asking for a passphrase, ask for it twice and complain if both inputs do not
match. Ignored on input from file or stdin.

--version, -V
Show the program version.

REPORTING BUGS

       Report bugs at cryptsetup mailing list <cryptsetup@lists.linux.dev> or in Issues project section
       <https://gitlab.com/cryptsetup/cryptsetup/-/issues/new>.

       Please attach output of the failed command with --debug option added.

CRYPTSETUP