A Dynamic Searchable Symmetric Encryption Scheme for Multiuser with Forward and Backward Security

Algorithm 1

FBM-DSSE.

	Setup:
(1)	input a security parameter
(2)	generate
(3)	set
(4)	set
	Update:
	data owner:
(1)	if then
(2)	extract keywords from the files
(3)	attach keys with column identifiers
(4)	for each column identifier
(5)
(6)	(match files to column identifiers and encrypt files)
(7)	for each file
(8)
(9)
(10)	if that does not match files
(11)
(12)
(13)
(14)	(generate bitmap index)
(15)	for each keyword
(16)
(17)
(18)	:
(19)
(20)
(21)
(22)
(23)
(24)
(25)	send to cloud server
(26)	else if
(27)	forming the
(28)	for each file
(29)	if
(30)
(31)	if
(32)
(33)
(34)	(reorder)
(35)
(36)
(37)	for each file
(38)
(39)	(generate the new index)
(40)	for each
(41)	if the
(42)
(43)
(44)
(45)	if the
(46)
(47)
(48)	for each
(49)
(50)
(51)
(52)
(53)
(54)
(55)
(56)
(57)
(58)	send to cloud server
(59)	send to users
	Search:
	user
(1)	if there is no updation, then
(2)
(3)
(4)	else
(5)
(6)
(7)
(8)	sends to cloud server
	cloud server:
(9)	if cannot be found in UL, then
(10)	output error
(11)	else
(12)
(13)
(14)
(15)	if
(16)
(17)	returns and to user