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Free disk encryption software for PCs and PDAs
(PDA version of WWW site)

Miscellaneous Notes

  • Please, do read the documentation (the FAQ section, in particular) before emailing questions! The FAQ section in particular may well have the answer you're looking for.
  • Both the PC and PDA versions of FreeOTFE, and FreeOTFE Explorer, are fully compatible with one another.
  • From the main window, doubleclicking on an item displayed will explore that item. Rightclicking brings up a context menu.
  • After creating a new FreeOTFE volume it is recommended that you make a backup of the volume's CDB.
    • In the case of volume files which have their CDB stored as part of the volume file, this can be achieved by selecting "Tools | Critical data block | Backup..."
    • In the case of volume files where the CDB is stored in a separate keyfile, simply make a backup copy of this keyfile.
  • A number of FreeOTFE volume properties can be changed via the "Tools | Change volume/keyfile password/details..." menuitem. Note that volumes must be dismounted first before they can be modified in this way.
  • An option is included to dump out a human readable version of the volume's critical data block/keyfile's contents (select "Tools | Critical data block | Dump to human readable file..."). This option is primarily intended to assist developers, and to future-proof volumes file by giving you access to the actual master encryption/decryption key used by the volume it dumps out. It should be noted that the inclusion of this option does not present a security risk as it requires that the user to enter the volume/keyfile's password immediately before it can operate (obviously, the volume/keyfile's password is needed in order to decrypt the critical data block). If an attacker has your volume/keyfile's password, clearly this option will give no further information away.
  • A "Revert timestamps" option is available from the "Options" dialog. If selected, on mounting a volume file its timestamps will be noted. When the volume is subsequently dismounted, these timestamps will be restored. By default, the PC version of FreeOTFE, and FreeOTFE Explorer, have this option switched on, and the PDA version (FreeOTFE4PDA) has it switched off. If you are going to use both the PC and PDA software with the same volume file, syncing between the two platforms, it is recommended that this option is turned off on both your PC and PDA installations, in order for ActiveSync to recognise when your volumes have been modified.
  • A password is not needed when backing up a volume's CDB as the backup copy is not stored in plaintext; it is a literal backup copy of a volume's (encrypted) CDB.
  • A password is needed when creating a keyfile as this requires that the volume's CDB is decrypted, before being re-encrypted with the keyfile's password and written out to the keyfile.
  • After new volumes are created, they will be automatically mounted and formatted. After this, it is highly recommended that you overwrite all the free space on the drive ("Tools | Overwrite free space"...)
  • Linux encryption settings files (".les") files are straightforward text files which contain the settings entered.
  • Peter Gutmann's "cryptlib" may (optionally) be used as an RNG, provided that it has been installed correctly. This may be downloaded from http://www.cs.auckland.ac.nz/~pgut001/cryptlib/. After installation, the "cryptlib" option will no longer be greyed out on RNG selection dialogs.
  • User settings configured via the "View | Options" menu are stored within a configuration file (".ini" file) which is located in the same directory the FreeOTFE Explorer executable is launched from. User options are not stored within the registry, unless configured to store them in it. By storing user settings in a separate file, as opposed to the registry, FreeOTFE Explorer achieves two things:
    1. If FreeOTFE Explorer is stored on removable media (e.g. a USB flash drive, CDROM), your settings can be stored together with FreeOTFE Explorer; there is no need to configure FreeOTFE Explorer every time you use it on a different computer - this would not be possible to do if the registry was used.
    2. When user settings are stored in a flat file, as opposed to the registry, security is increased. It is trivial to overwrite a simple file if needed, but removing registry entries completely is another matter.
  • Creating an encrypted partition/disk will overwrite whatever data was stored on the partition/disk you select. Be careful!