Linkable Ring Signature Scheme Using Biometric Cryptosystem and NIZK and Its Application

Algorithm 4

Sign (, , ).

	Input: , , , , .
	Output: .
(1)	Let .
(2)	Compute , and where
(3)	.
(4)	Compute , .
(5)	for do
(6)	Choose
(7)	Compute ; ;
(8)	;
(9)	end
(10)	Compute .
(11)	for do
(12)	for do
(13)	Choose
(14)	Compute ;
(15)	;
(16)	end
(17)	Compute ;
(18)	end
(19)	for do
(20)	Compute ;
(21)	end
(22)	return .