We propose a new Bloom filter that efficiently filters out non-members. With extra bits assigned and asymmetrically distributed, the new filter reduces hash computations and memory accesses. For an error rate of 10-6, the new filter reduces cost by 31.31% with 4.33% additional space, while the standard method saves offers a 20.42% reduction.

New payment technologies are coming that will raise user convenience. To support automatic hands-free payment, merchant devices will collect customer's information from the cloud of payment service providers or customer's smart phones, which should be removed after the transaction. Using Jaccard containment, we propose a proactive security approach of cleaning personal data at merchant-side point-of-sale terminals. We also propose a sampling method to reduce communication overhead by several orders of magnitude.