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Re: ADS Password Storage Protection
From: Michael Rice <michael () riceclan org>
Date: Mon, 24 Jul 2006 17:40:13 -0500

Ansgar -59cobalt- Wiechers wrote:

On 2006-07-20 Roger A. Grimes wrote:
Here is my statement: That password length is a better defender of
passwords than complexity, character for character, and that length
should at least be given equal treatment when creating strong
passwords.

I agree with the latter of your statement, but the former is plain
wrong. Length and complexity are equivalent, i.e. you can increase
either length or complexity (or both of course) to make a stronger
password. That's pretty obvious if you think about e.g. base64-encoding
a password: the encoding increases the length and decreases the
complexity, but doesn't affect the strength at all. It's due to the
physical limitations of keyboards that it's usually easier to increase
the length than the complexity.

I think his assertion works out mathematically. The possible combinations of 6 character passwords using only lowercase letters of the alphabet are

26^6 = 308915776

The possible combination of 16 character passwords using only lowercase letters are:

26^16 = 43608742899428874059776

The possible combinations of 6 character passwords using a-zA-Z0-9 and your favorite 32 punctuation:

95^6 = 735091890625

You can see, in n^k, increasing k means increasing the outcome much faster than increasing n. Increasing the possible combinations means increasing the time to discover the password through pure brute force methods.

Once humans are introduced, it becomes more complicated than this.

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