A system for equality testing, the system comprising a first client device including a first private data unit, a second client device including a second private data unit, and a server. The server receives a first obfuscated data unit corresponding to the first private data unit from the first client device, and a second obfuscated data unit corresponding to the second private data unit from the second client device. The server performs a vector calculation based on the first and second obfuscated data units to generate a combination of the first and second obfuscated data units. The server sends the combination to the first client device. The first client device is configured to determine whether the first private data unit is equal to the second private data unit based on the combination.