[dm-crypt] Note: Characters inadvisable in Passphrases
arno at wagner.name
Sat Jul 9 00:34:41 CEST 2011
On Sat, Jul 09, 2011 at 12:05:11AM +0200, Milan Broz wrote:
> On 07/08/2011 11:11 PM, Arno Wagner wrote:
> > So it is highly advisable to stay within the 94 printable
> > characters on the standard, 128 character ASCII table. The
> > table can e.g. be found here: http://en.wikipedia.org/wiki/ASCII
> These suggestions also highly depends on environment (e.g. keyboard map).
Not so bad, since then you can still put the passphrase into a file
using a hex-editor and read it from there if you stay in ASCII 7 Bit.
If you do not know the original encoding, that can be a problem
or at least take a lot of experimenting.
> (An example of local problem is if using Czech/English keyboard switch
> ("password1234 is not password+??????") or with qwerty/qwertz layout
> and suggestions like "try to not use y/z in passphrase to avoid the problem".
> Another common problem is "please check that you have NumLock
> switched on when entering digits".
> Of course, 5 of 4 admins likes late night calls from users crying
> "my password doesn't work!"... :-)
> That said, there is no limitation in cryptsetup or dmcrypt regarding
> input character set.
> All these suggestions are quite generic and are intended to prevent
> problem with different environments (locales, keyboard layout etc).
> (My suggestion is better use longer non-dictionary ascii-friendly
> passphrase than using non-ascii characters in it. But if you
> disagree, just ignore this suggestion - it will work.... until
> you need to unlock external drive on system with foreign keyboard
> and locales... :-)
I completely agree. :-)
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno at wagner.name
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