I am trying to implement the protocol mentioned in Section 3.4 of “Efficient Robust Private Set Intersection” in Java.
In the Second Step, the Client computes a polynomial of degree $n$ over the finite field.
For $C=\{1,2\}$, will the Polynomial be $x^2-3x+2$?
Can the polynomial have negative coefficients over the finite field? If yes, how do I encrypt the negative coefficients using Additive ElGamal?
