Looking at just EC Public Key parameters, how can you tell if it is invalid?
The general rule for curves is given in;

2003 - Validation of Elliptic Curve Public Keys by Adrian Antipa,Daniel Brown, Alfred Menezes, and René StruikScott Vanstone
They defined a point is valid if

$P \neq \mathcal{O}$
The $x$ and $y$ coordinates of $P$, $x(P),y(P)$ are valid elements of the field.
$P$ satisfies the curve equation - against the twist attack
Check $[n]P = \mathcal{O}$ for prime curves ($h=1$) and check $[h]P \neq \mathcal{O}$ for non-prime curves ($h&gt;1$) where $h$ is the cofactor $h = \#E(k)/n$



if 1,2, and 3 are verified and $h=1$ (i.e. prime curve) then the 4th is already satisfied.