We study the following problem: $B_0$ and $B_1$ each has a sparse input vector $V_0$ and $V_1$; for each $j$ we need to decide whether $B_0[j]+B_1[j]>t$. We give a privacy-preserving algorithm, in which $B_0$ and $B_1$ do not need to reveal any information about their input vectors to each other, except the output of algorithm. Our algorithm is highly efficient.
Sheng Zhong. "Privacy-Preserving Distributed Algorithm for Sparse Vector Sum." Bull. Belg. Math. Soc. Simon Stevin 17 (2) 235 - 242, april 2010. https://doi.org/10.36045/bbms/1274896202