You havent proved anything here. (Except that you dont understand how my solution works, the list you built meant my code was trying to match all _4_ digit fuzzy strings, and not the _2_ digits we were originally discussing, this presumably is where you get the misconception that it wont handle 25 digit keys.) The behaviour you have posted here is exactly as I predicted. And its correct. As I stated in my earlier post and as ysth pointed out as well its trivial to determine what keys also match if a given key matches. So you havent proved anything here. I could have written the code so that instead of outputing only the literal string matched it would output a precalculated list of all the possible variants. Which actually brings me to yet another mathematical problem with your code. Your list omits the 30 words that have only 1 digit different.

Point in fact you say my idea doesnt work. So I posted working code. Then you say its broken, when in fact it does exactly what it was advertised to do. Face it BrowserUk you are and were wrong. Your XOR approach is slow, so slow as to be useless for nontrivial searches. The state machine is fast, and where it has an up-front overhead can be reused over and over. No matter what you do you arent going to get around that. Sorry.

I suggest you drop this, all you are doing is embarrasing yourself now.