Well, directly is a bit of a stretch. It's probably more fair to say they're directly based off the Powers-Lehmer-Morrison-Brilhart (also Kraitchik, for the dis

Well, directly is a bit of a stretch. It's probably more fair to say they're directly based off the Powers-Lehmer-Morrison-Brilhart (also Kraitchik, for the discrete log) method, which introduced the concept of factor bases and combining relations to find a difference of squares.