A New Bloom Filter Structure for Searchable Encryption Schemes

We propose a new Bloom filter structure for searchable encryption schemes in which a large Bloom filter is treated as (replaced with) two smaller ones for the search index. False positive is one inherent drawback of Bloom filter. We formulate the false positive rates for one regular large Bloom filter, and then derive the false positive rate for the two smaller ones. With examples, we show how the new scheme cuts down the false positive rate and the size of Bloom filter to a balanced point that fulfills the user requirements and increases the efficiency of the structure.