Rumgeilt was later in the English translation of the article.
I know a little German, a little French and took Classical Greek in college, as well as Intro to Linguistics (where, iirc, we covered a bit of Swahili grammar for some damn reason). I am pretty comfortable with both weird idioms not translating directly and with finding close, if uncommon, matches between some other language and words or phrases in English. So, the "in turn" part doesn't disturb me. I mean, you could translate it as something like "They are taking it in turns" or "but the methods to crack it also got their turn to improve."
Is what it was trying to translate, not sure where you/it got 'rumgeilt' from.
A more natural sounding translation would be:
The technology has improved since then, but, on the other hand, so have the methods to crack it
You could also translate 'wiederum' as 'in turn' which might exlain the 'turn' in Google's translation.