cryptsetup-fvault2Dump(8) — Linux manual page



NAME         top

       cryptsetup-fvault2Dump - dump the header information of a FVAULT2
       (FileVault2 compatible) device

SYNOPSIS         top

       cryptsetup fvault2Dump [<options>] <device>

DESCRIPTION         top

       Dump the header information of a FVAULT2 (FileVault2 compatible)

       If the --dump-volume-key option is used, the FVAULT2 device
       volume key is dumped instead of header information. You have to
       provide password or keyfile to dump volume key.

       Beware that the volume key can be used to decrypt the data stored
       in the 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, --volume-key-file,
       --key-file, --keyfile-offset, --keyfile-size, --timeout].

OPTIONS         top

       --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

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

       --keyfile-offset value
           Skip value bytes at the beginning of the key file.

       --keyfile-size, -l value
           Read a maximum of value bytes from the key file. The default
           is to read the whole file up to the compiled-in maximum that
           can be queried with --help. Supplying more data than the
           compiled-in maximum aborts the operation.

           This option is useful to cut trailing newlines, for example.
           If --keyfile-offset is also given, the size count starts
           after the offset.

       --volume-key-file, --master-key-file (OBSOLETE alias)
           Use a volume key stored in a file. The volume key is stored
           in a file instead of being printed out to standard output.

       --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.

       --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

           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.

       --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.

       --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.

       --version, -V
           Show the program version.

           Show short option help.

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

REPORTING BUGS         top

       Report bugs at cryptsetup mailing list
       <> or in Issues project section

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

SEE ALSO         top

       Cryptsetup FAQ

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

CRYPTSETUP         top

       Part of cryptsetup project
       <>. This page is part of
       the Cryptsetup ((open-source disk encryption)) project.
       Information about the project can be found at 
       ⟨⟩. If you have a bug
       report for this manual page, send it to This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2023-12-22. (At
       that time, the date of the most recent commit that was found in
       the repository was 2023-12-20.) If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

cryptsetup 2.6.1-git           2022-12-14      CRYPTSETUP-FVAULT2DUMP(8)

Pages that refer to this page: cryptsetup(8)