Also diff. rises each day
The difficulty rises every 10 to 14 days, not every day.
Can someone please explain me in simple terms, that in a distributed system like bitcoin network, how the need to increase difficulty is programmaticaly determined ?
The difficulty is recalculated every 2016 blocks based on the amount of time it took to produce the previous 2016 blocks, according to the timestamps.
D
new = D
old x 14 days / actual time for the last 2016 blocks
Since the actual time for the last 2016 blocks is agreed on by everyone, everyone computes the same difficulty value.