Say we have these following parameters,
q : A k-bit prime
$F_q$ : A prime finite field
$E/F_q$ : An elliptic curve E over $F_q$
G : A cyclic additive group of composite order q
P : A generator for group G
s : A secret key of trusted authority center
$PK_{TAC}$ : A public key of the trusted authority center, $PK_{TAC}=sP$
Now, I want to obtain $s$ from the equation $PK_{TAC}=sP$, can I simple solve it like $s=\dfrac{PK_{TAC}}{P}.$
I asked my instructor about this, what she told is that elliptic curve is a discrete log problem so we cant do it, but I am not getting how elliptic curve is even related to that equation. Any help will be really great. Thank you.