Analysis and Improvement of Blockchain-Based Multilevel Privacy-Preserving Location Sharing Scheme for Telecare Medical Information Systems

Algorithm 8

Location sharing.

	Input:
	Location record ; LDO’s secret keys and (); Privacy protection level ; LDR’s public-key
	Output:
	Shared location information
(1)	;
(2)	choose a session key
(3)	ifthen
(4)
(5)	else ifthen
(6)	find such that
(7)
(8)
(9)	find such that
(10)
(11)
(12)	; ;
(13)	; ;
(14)	; ;
(15)	; ;
(16)	;
(17)	; ;
(18)
(19)	;
(20)
(21)	end if
(22)	return.