the lines the server asks us to decrypt are the same in every level. so you could get them all in the first lvl and then just <map(len, word.split( ' ' ))> and you would get a signature for each line.
Then, in levels 2 to 6, you could just <map(len, word.split( enc(' ') ))> the line you receive and then look for that signature in the list. It would fail on lvl 7.

wow...that escape XD