A protocol for secure distributed spatial searching using homomorphic encryption.

Privacy of a person doing a spatial search as well as security of data being provided by a data provider can be of great concern in collecting statistical data. This has led to those who engage in searching for data to ask questions on whether they are anonymous to the one who is providing the data and also
whether the one who is providing the data is anonymous to those who are doing the searching. However, such questions have provided an opportunity to the computer science community (researchers) to seek for solutions that can be used to deal with this problem of lack of anonymity of data and confidentiality.
This study therefore aimed to propose a protocol by putting into application Homomorphic Encryption and a Distributed Ring Algorithm, to ensure anonymity of data of both parties involved in a spatial search, that is, a data provider and a searcher. To achieve this aim, three objectives were set. The first objective was to identify a Homomorphic Encryption technique that can support a spatial search. This was achieved by reviewing literature on Homomorphic Encryption techniques. Paillier Homomorphic Encryption technique was identified as the best approach that can support a spatial search. The second objective was to develop a protocol for distributed spatial searching based on the best Homomorphic Encryption technique which was identified. After analysing how Pallier Encryption works, a protocol was then designed based on distributed system principles. The third objective was to develop a proof of concept using the proposed protocol. A prototype implemented as distributed application was written in Java using the proposed protocol. The study implemented an application from the protocol developed which proved useful for collecting statistical data with guaranteed confidentiality. It also proved that, by putting into application Homomorphic Encryption, the person who was doing the search became anonymous to the providers of the data and the data provided by the providers became anonymous to the person who was doing the searching.