CRYPTSETUP-TCRYPTDUMP(8)

📦
version 2.8.8 · 17 versions
, in arch rolling, fedora 44, nixpkgs unstable

CRYPTSETUP-TCRYPTDUMP 💅✨

okay bestie, buckle up — this is the cryptsetup-tcryptDump page from the cryptsetup manual (section 8, maintenance commands division, iykyk). It's the one that dumps header info off a TCRYPT device, and I'm gonna walk you through every single flag because we do not skip details in this house. 🫶

✨ NAME ✨

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

✨ SYNOPSIS ✨

cryptsetup tcryptDump [<options>] <device>

✨ DESCRIPTION ✨

So basically, this command dumps the header information of a TCRYPT (TrueCrypt or VeraCrypt compatible) device. That's the whole vibe. 🦋

If you throw in the --dump-volume-key option, then instead of the TCRYPT header info you get the TCRYPT device volume key dumped instead. And bestie, listen — beware: that volume key (or the concatenated volume keys, if a cipher chain is in play) can be used to decrypt the data stored in the TCRYPT container without a passphrase. Which means if the volume key gets compromised, the whole device has to be erased to stop any further access. Use that option carefully, fr fr. 💀

The --key-file option lets you combine file content with the passphrase. And yes, the --key-file option can be repeated. Important: using keyfiles here is different from LUKS keyfile logic, so don't go assuming they behave the same. 🙈

<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]. 🌸

✨ 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 the plain device type. For the tcrypt device type, it restricts the checked cipher chains when looking for the 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). See the 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 the tcrypt device type, it restricts the checked PBKDF2 variants when looking for the 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 the 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 file — Read the passphrase from the 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 the 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 the 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 that is 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 seconds — The number of seconds to wait before a 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 the VeraCrypt device. See the 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 the Issues project section <https://gitlab.com/cryptsetup/cryptsetup/-/issues/new>. 🐛

Please attach the output of the failed command with --debug option added. (Yes, that part actually matters, bestie — attach the debug output or they can't help you. 😤)

✨ SEE ALSO ✨

Cryptsetup FAQ <https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions>

cryptsetup(8), integritysetup(8) and veritysetup(8) 🌈

✨ CRYPTSETUP ✨

Part of cryptsetup project <https://gitlab.com/cryptsetup/cryptsetup/>. 👑

and that's the whole page, no notes 💅 — this was cryptsetup version 2.8.8, dated 2026-09-07, from the cryptsetup project. go dump some headers responsibly, bestie 🎀✨🦋

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