Practical and Secure Integer Comparison and Interval Check

We propose a solution to the secure integer comparison problem by reducing it to the secure set membership problem on a set where the elements occur in consecutive order. Our protocol provides flexibility due to this reduction such that it can easily be modified to support more complex boolean functions other than the function evaluating the 'Less Than' predicate (LT). In the paper we show one such boolean function, 'IsInInterval', which checks if an integer is in an interval (3I). We also show that our protocols can be easily extended to support shared outputs so that each party would hold a share of the result. Our generic solution can be applied to many e-commerce and data-mining applications requiring one or more such boolean functions to be computed securely. Our protocol not only is adaptable to different boolean functions but also is experimentally more efficient than the state-of-the-art integer comparison protocols supporting shared outputs.