Question

Last time we were talking about the BFV algorithm for homomorphic computation. The notation z_q is to sample coefficients from the range of?

Options:
Option 1: (0, q)
Option 2: (-q/2, q/2]
Option 3: (-q/2, 0]
Option 4: (-q, q]

Answer 1

The notation z_q is used to sample coefficients from the range of (-q/2, q/2].

Step-by-step explanation:

The notation zq is used to sample coefficients from the range of option 2: (-q/2, q/2]. In the BFV algorithm for homomorphic computation, zq represents a random coefficient in the range [-q/2, q/2] that is used for encryption. The reason why the range is (-q/2, q/2] instead of (-q/2, 0] or (0, q) is to allow for a more efficient and secure implementation of the algorithm.