# Re: How Many Permutations Make a Password Effectively Impossible to Brute Force Calculate?

*From*: "W" <persistentone@xxxxxxxxxxxxxx>*Date*: Tue, 15 Mar 2011 14:41:07 -0700

"Thor Kottelin" <thor@xxxxxxxx> wrote in message

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"W" <persistentone@xxxxxxxxxxxxxx> wrote in message

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"unruh" <unruh@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message

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On 2011-03-14, W <persistentone@xxxxxxxxxxxxxx> wrote:24

If you construct a password from smallcase letters, you effectively

have

andpermutations per character. If you construct a password from

uppercase

permutationslowercase and add in 10 number digits, you increase that to 58

per character in the password.

How many permutations effectively make it impossible - with modern

computers - to brute force calculate a password?

Depends on how long you are willing to spend.

I don't think that's quite correct. At a certain number of

permutations, even 10K computers couldn't brute force the password in 10

years, working 24x7.

I'm trying to objectify this. So "depends" isn't a useful answer.

I am not a cryptologist, but I think an exact answer would require exact

values for "modern computers", both in terms of quantity and performance.

Does the attacker have access to a couple of PCs, to a botnet grid or to

the combined supercomputer capacity of several Western governments?

The attacker has 10K Intel 3GHz quad core computers.

You are probably familiar with the results e.g. distributed.net has

achieved.

No I am not.

--

W

.

**References**:**How Many Permutations Make a Password Effectively Impossible to Brute Force Calculate?***From:*W

**Re: How Many Permutations Make a Password Effectively Impossible to Brute Force Calculate?***From:*unruh

**Re: How Many Permutations Make a Password Effectively Impossible to Brute Force Calculate?***From:*W

**Re: How Many Permutations Make a Password Effectively Impossible to Brute Force Calculate?***From:*Thor Kottelin

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