Toward a More Accurate Accrual to Clinical Trials: Joint Cohort Discovery Using Bloom Filters and Homomorphic Encryption.Reliable cohort discovery is an essential early part of clinical study design.  A two-party Elgamal protocol is implemented to ensure privacy and security imperatives, and a special attribute of Bloom filters is exploited for accurate and fast cardinality estimates. 
Bloom Filters
Toward a More Accurate Accrual to Clinical Trials: Joint Cohort Discovery Using Bloom Filters and Homomorphic Encryption.Reliable cohort discovery is an essential early part of clinical study design. 
Homomorphic Encryption
A two-party Elgamal protocol is implemented to ensure privacy and security imperatives, and a special attribute of Bloom filters is exploited for accurate and fast cardinality estimates. 
Elgamal protocol