I could see this as being a good strategy if you didn't declare it, but by eliminating vowels you reduce the search space.
 
It's only a good tactic if people actually switching from using dictionary words to using something with higher entropy. More likely though, you'll start to see things like 'bbbddq' or 'cmplt sntnce,' and the users will still be susceptible to dictionary attacks.
 
It's important to remember that a good dictionary attack has a dictionary that is much larger than a list of words in different languages, it also has common patterns. This sort of restraint probably reduces the usage of dictionary words but increases the usage of other common patterns.
 
I don't like it.


On Mon, Nov 11, 2013 at 7:29 AM, J.A. Terranson <measl@mfn.org> wrote:

Mildly interesting, for those who have an interest ?


//Alif

--
Those who make peaceful change impossible,
make violent revolution inevitable.

An American Spring is coming:
   one way or another.


---------- Forwarded message ----------
Date: Thu, 7 Nov 2013 14:01:15 -0500
From: William Arbaugh <warbaugh@gmail.com>
To: dailydave@lists.immunityinc.com
Subject: [Dailydave] Don't use vowels in passwords!

According to the Defense Finance and Accounting Service (DFAS), you shouldn't use vowels in your password!

The DFAS web site myinvoice.csd.disa.mil is instituting new password requirements starting tomorrow. The details can be found at the site (if you're willing to read a PDF hosted by DOD that is).

DFAS brings us two significant improvements to password/PIN security by forbidding the use of vowels, and requiring that password/PINs be EXACTLY 15 characters long (no more, no less). I'd guess that the first requirement is to prevent people from using dictionary words. The second requirement is probably due to some obscure issue with their use of an Oracle Java front-end.

This is from a web site that until recently ( and I believe still does) required the use of IE and Java 6. Logging in use to require clicking through no less than 3-4 security warning pop-ups.
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