3. consensus algorithm
Yes, that's the correct term.cygan answered most of it. I wonder how did cygan manage to guess those words.
Maybe he is really good at solving puzzles and riddles, if you can call it that. And it helps if he is familiar with the terminology and have seen the words in various texts. Or he has a huge database of terms and a script/software that can find those that match according to the provided letters. Who knows 
Round #4 is complete. Stay tuned for the next one!