In all the talk of super computers there is not...

[Allen]

There does not seem to be much consideration about what is 
computationally infeasible, even with rainbow tables.

If I remember correctly an 8 character 94 key space table is 
about 300 MB. How big would it be if it was covering 12 
characters? How long would it take to compute assuming 1,000 3 
GHz CPUs on a bot net?

Now take the phrase "Mary had a lamb, and its fleece was as white 
as snow." Not counting the quotes it is 52 characters and has 
both upper and lower case characters, spaces and two specials or 
a total of 55 key space. How big would the rainbow table be to 
contain that? How long would it take to compute with 1,000 3 GHz 
CPUs?

Of course one could not assume that the pass phrase would only 
have the 55 above, so what about the 94 key space table for 52 
characters? How big? How long to compute?

 From the spreadsheet I have it runs out of space to calculate 
and just renders errors.

I'm guessing that even the botnets in current use couldn't do it 
in any reasonable time frame nor is the storage space available 
at an affordable price for any but three letter agencies.

Am I correct?

Allen

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