Complex sentence: This is a reduction of almost 3 orders of magnitude from the at most 10,000,000 possible PINs that would have to be tested absent the flaw, and, as a result, a practical attack can be completed in just a few hours.
Split into simpler sentences: This is a reduction of 3 orders of magnitude from the number PINs that would have to be tested absent the flaw. As a result, a practical attack can be completed in just a few hours.