Since we're looking at b64encoded strings at this point, we can just lop it off at 200 characters. I think that's a better idea than doing it earlier. When I originally implemented this, I had it truncate earlier in the algorithm to save some cpu since doing operations on 50 characters is a lot faster than a might-as-well-be-infinite number of characters. However, since then, we imposed a 10000 character max and these operations should be fast enough on 10000 characters that it shouldn't be noticeable.