According to Representing a function as FHE circuit, the AND gate for FHE encrypted data is just
A*B, in the case that the plaintext has only
Remember that on the BFV FHE scheme, it encrypts polynomials, and we can set the maximum value of the coefficients of the polynomial. So, if we set the max value to
1, then we can do binary gates easily. For example:
1 + 0x^1 + 1x^2 + 0x^3 + 0 + 1x^1 + 1x^2 + 0x^3 ______________________ 1 + 1x^1 + 0x^2 + 0x^3
+ is essentially the OR gate for the polynomials. But I'm strugling to understand
* as being the AND, specially because the multiplication of these polynomials are
mod x^n +1, where
n is the degree of the polynomials. So it's not a simple multiplication.
AND = *?