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Comment by theblackbox | Hacker News Reader

Would the contest have been any easier had one made the (dubious) assumption that the "passphrase" encoded would likely be a valid sentence?

I've not tried any crypto work before but this has really grabbed my interest. It just occurred to me however, that discarding lines of inquiry leading down the "BuGS bugs bUgs BUGs BLAnK BlAnK....." route in favour of something that made more sense grammatically could be a good tactic to save time?.... or it could just increase the overhead in generating the next hash?...

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Unless you found the exact sequence, the difference between hashes won't tell you how close you are.

I don't see what you mean by "the difference between hashes won't tell you how close you are" .... isn't that the whole point of this competition?

Say for instance you coded four stages:

1/ Generating a list of strings for analysis 2/ Parsing that list for sentences that made sense 3/ Hashing these sentences 4/ Comparing the hashes generated with the one being sought

to me it just looked as though a lot of gibberish was analysed because there is a lot more entropy than order to sift through and nobody tried step 2... does my logic make sense or am I getting mixed up and not really seeing the bigger picture?

Suppose the hash for a specific phrase was completely random, but fixed. (Which is not too far off for a cryptographic hash-function.)

So unless you want to find the exact sequence, it does not matter whether you candidate strings make sense or not. And since the search space is so large, people just gave up on finding the exact sequence. They just use a lot of cycles to find any sequence, that is close in hash.

There's no benefit in trying step 2 because the gibberish input is as likely to be a close match as a sentence that makes sense.

A sentence that starts 'Be' (001000010...) and the same sentence changed to 'He' (001001000...) would produce very different hash results by the Avalanche Effect ( http://en.wikipedia.org/wiki/Avalanche_effect ). So having similar letters in a similar order or in similar positions, or using similar length words, wont help.

Isn't that the whole point of this competition?

The point was to get a hash with a similar quantity of 0 and 1 bits in the output as their hash, not to guess their sentence (they said what it was).

The point was ... not to guess their sentence (they said what it was).

Ahh, I missed that! That makes sense in terms of the Avalanche Effect - cheers for the knowledge

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