The fastest 100 in cricket was hit by Shahid Afridi in 37 balls.
shahid afridi forever
shahid afridi (pakistan)
Shahid Khan Afridi in just 37 Balls
Shahid Khan Afridi
It was Shoaib Akhtar's ball, which is 100 mph or 161 kph.
Not only 100,he holds the record of taking fastest 200 wickets as well.