When calculating the general public key, what precept is used to take the even or odd y coordinate for x?

It isn’t chosen; it’s computed.

The elliptic curve level multiplication algorithm outputs a degree, which has an X and Y coordinate.

Whereas it’s true that negating the personal key will negate the general public key’s Y coordinate, there is no such thing as a easy rule for figuring out what the parity of Y will probably be with out really performing the elliptic curve multiplication operation. In truth, there can’t be such a rule; it might represent a break within the discrete logarithm safety of the curve.

It isn’t chosen; it’s computed.

The elliptic curve level multiplication algorithm outputs a degree, which has an X and Y coordinate.

Whereas it’s true that negating the personal key will negate the general public key’s Y coordinate, there is no such thing as a easy rule for figuring out what the parity of Y will probably be with out really performing the elliptic curve multiplication operation. In truth, there can’t be such a rule; it might represent a break within the discrete logarithm safety of the curve.