Natural Backdoor Attacks on Deep Neural Networks via Raindrops

Algorithm 1

Raindrops-Trigger Generation.

	Given: begin training data , poison injection rate , trigger density , blur kernel and , mask .
	Output: dataset with trigger
(1)	, ,
(2)	random select samples with ratio from
(3)	for all    do
(4)
(5)	if
(6)
(7)	else
(8)
(9)
(10)
(11)
(12)
(13)	end for
(14)	return