# cryptsetup-fvault2Dump

## NAME



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


## SYNOPSIS



           **cryptsetup** _fvault2Dump_ **[ <options>] <device>**
    


## DESCRIPTION



           Dump the header information of a FVAULT2 (FileVault2 compatible)
           device.
    
           If the --dump-volume-key option is used, the FVAULT2 device volume
           key is dumped instead of header information. You have to provide a
           password or keyfile to dump the 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



           **--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.
    
           **--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.
    
           **--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.
    
           **--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.
    
           **--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.
    
           **--version** , **-V**
               Show the program version.
    
           **--volume-key-file** _file_ , --master-key-file 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.
    


## CRYPTSETUP



           Part of cryptsetup project
           <https://gitlab.com/cryptsetup/cryptsetup/>. This page is part of
           the _Cryptsetup_ ((open-source disk encryption)) project.
           Information about the project can be found at 
           ⟨https://gitlab.com/cryptsetup/cryptsetup⟩. If you have a bug
           report for this manual page, send it to dm-crypt@saout.de. This
           page was obtained from the project's upstream Git repository
           ⟨https://gitlab.com/cryptsetup/cryptsetup.git⟩ on 2025-08-11. (At
           that time, the date of the most recent commit that was found in
           the repository was 2025-08-01.) 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
           man-pages@man7.org
    
    cryptsetup 2.8.1-git            2025-08-09      _CRYPTSETUP-FVAULT2DUMP_(8)
    


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