Privacy-Preserving Point-Line Relation Determination Protocol and Its Applications

A privacy-preserving point-line relation determination protocol based on additive homomorphism encryption is developed in semi-honest model.The privacy-preserving point-line relation determination protocol can be used to solve many privacy-preserving computational geometry problems,such as segments intersection problem and point inclusion problem.The privacy-preserving point-line relation determination protocol can be also used to determine either the point is at the positive side,negative side,or on the line privately.Further more,the privacy-preserving segments intersection protocol can be used to determine two lines supplied by different users intersect securely;and the privacy-preserving point inclusion protocol can be used to determine the relation of a point and a polygon supplied by different users.Finally,the correctness,security and efficiency of these protocols are analyzed.