Hacker News Reader

Comment by netsharc | Hacker News Reader

Here's what "four" and "some" look like: https://i.imgur.com/UNSpv6v.png . Different letter widths and kerning make this identification possible.

I wonder how brute-forceable it is. Given a blank with length of half a line, can I just throw 20-30 combination of the alphabet and punctuation, and figure out which combinations match, and the anagram for it?

Actually, brute-forcing using words from a dictionary (English words plus names of the involved people (Americans, and obviously Russians)) would make it go even faster.

View on HN

In theory kerning differences would make letter ordering significant, so this becomes a permutation problem not a combination problem, and therefore much harder to brute force.

But valid sentence fragments are not random draws from an alphabet, they're drawn from a dictionary, which makes it much easier.

Is kerning used also across spaces? I.e is the space between two words dependent on which letter the first word ends with, and which letter the second word starts with?

If not, it still seems tractable using dictionary words.

> Is kerning used also across spaces?

Yes.

Ok. Makes it much more difficult. Still, assuming grammatically valid sequences of dictionary words, kerning would be known both within and between words. These texts however probably contain lots of abbreviations, footnote symbols, numbers, brackets etc, that make it likely to be a lot harder than just regular prose from dictionary words.

Did you mean this becomes a combination problem not a permutation problem?

It's been a while since my last discreet math class so take this with a grain of salt, but in a combination you only care about selecting the correct members of a set, so order does not mater. In a permutation problem you care about selecting the correct members as well as their order, so it is a significantly larger solution space which expands factorially.

Thanks for pointing tjat out. So if they are to leave the original layout --not padding the spacing or subtracting spacing asf. then they should at a minimum use monospaced typefaces.

Reply on news.ycombinator.com