Order-Revealing Encryption Scheme with Comparison Token for Cloud Computing

Algorithm 1

Secure BF.

	Input:
	hash function:
	secret keys:
	data item:
	Output:
	–Bloom filter:
(1)	In order to hide the frequency, DO adds a random fractional part for the data item as , where has the same number of bits with the data item and is a -bit number;
(2)	DO computes prefix family of as ;
(3)	for to do
(4)	To remove the correlation among different nodes, DO chooses a random number which has the same size with secret keys ;
(5)	for j←1 to s do
(6)	DO first computes hash value and then sets 1 on the position ;
(7)	end for
(8)	end for
(9)	After inserting the prefix family, we have a secure Bloom filter .