GBDE(8) BSD System Manager’s Manual GBDE(8)


gbde — operation and management utility for Geom Based Disk Encryption


gbde attach destination [−l lockfile] [−p pass-phrase]
gbde detach
gbde init
destination [−i] [−f filename] [−L lockfile] [−P pass-phrase]
gbde setkey
destination [−n key] [−l lockfile] [−p pass-phrase] [−L new-lockfile] [−P new-pass-phrase]
gbde destroy
destination [−n key] [−l lockfile] [−p pass-phrase] [−L lockfile]


NOTICE: Please be aware that this code has not yet received much review and analysis by qualified cryptographers and therefore should be considered a slightly suspect experimental facility.

We cannot at this point guarantee that the on-disk format will not change in response to reviews or bug-fixes, so potential users are advised to be prepared that dump(8)/restore(8) based migrations may be called for in the future.

The gbde utility is the only official operation and management interface for the gbde(4) GEOM based disk encryption kernel facility. The interaction between the gbde utility and the kernel part is not a published interface.

The operational aspect consists of two subcommands: one to open and attach a device to the in-kernel cryptographic gbde module, and one to close and detach a device.

The management part allows initialization of the master key and lock sectors on a device, initialization and replacement of pass-phrases and key invalidation and blackening functions.

The −l lockfile argument is used to supply the lock selector data. If no −l option is specified, the first sector is used for this purpose.

The −L new-lockfile argument specifies the lock selector file for the key modified with the setkey subcommand.

The −n key argument can be used to specify to which of the four keys the operation applies. A value of 1 to 4 selects the specified key, a value of 0 (the default) means ’’this key’’ (i.e., the key used to gain access to the device) and a value of −1 means ’’all keys’’.

The −f filename specifies an optional parameter file for use under initialization.

Alternatively, the −i option toggles an interactive mode where a template file with descriptions of the parameters can be interactively edited.

The −p pass-phrase argument specifies the pass-phrase used for opening the device. If not specified, the controlling terminal will be used to prompt the user for the pass-phrase. Be aware that using this option may expose the pass-phrase to other users who happen to run ps(1) or similar while the command is running.

The −P new-pass-phrase argument can be used to specify the new pass-phrase to the init and setkey subcommands. If not specified, the user is prompted for the new pass-phrase on the controlling terminal. Be aware that using this option may expose the pass-phrase to other users who happen to run ps(1) or similar while the command is running.


To initialize a device, using default parameters:

gbde init /dev/ad0s1f -L /etc/ad0s1f.lock

To attach an encrypted device:

gbde attach ad0s1f -l /etc/ad0s1f.lock

The encrypted device has the suffix .bde so a typical command to create and mount a file system would be:

newfs /dev/ad0s1f.bde
mount /dev/ad0s1f.bde /secret

To detach an encrypted device:

gbde detach ad0s1f

Please notice that detaching an encrypted device corresponds to physically removing it, do not forget to unmount the file system first.

To initialize the second key using a detached lockfile and a trivial pass-phrase:

gbde setkey ad0s1f -n 2 -P foo -L key2.lockfile

To destroy all copies of the masterkey:

gbde destroy ad0s1f -n -1


gbde(4), geom(4)


This software was developed for the FreeBSD Project by Poul-Henning Kamp and NAI Labs, the Security Research Division of Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 (’’CBOSS’’), as part of the DARPA CHATS research program.


Poul-Henning Kamp <phk [AT]>


The cryptographic algorithms and the overall design have not been attacked mercilessly for over 10 years by a gang of cryptoanalysts.

BSD October 19, 2002 BSD