I was looking up a tutorial that talked about the finite field and discrete log problem. It's said that solving for $k$ in $b^k=a$ is a problem that is difficult.
The example given was: What power do I raise some number $b$ to, to get $a$? It then mentions that this could be a one-way function.
What I don't understand is, how is this difficult to solve and why is it a one-way function?
For example, if $b=3$ and $a=99$, I suppose we can solve $k$ by just doing $\log_{3}(99)=4.18265...$, is that right? The only issue I could see here is there is no solution for an integer number since $4.182$ is a real number. And why does it say this is a one-way function since we can use log to get the values back and forth?