How to Solve any Protocol Problem - An Efficiency Improvement

Consider n parties having local inputs x 1,x 2,...,x n respectively. and wishing to compute the value f(x 1,...,x n). where f is a predetermined function. Loosely speaking. an n-party protocol for this purpose has maximum privacy if whatever a subset of the users can efficiently compute when participating in the protocol, they can also compute from their local inputs and the value f(x 1,..., x n).