Yes and no. Certain algorithms make it harder to do timing-resistant implementations, but by no means impossible. Probably the easiest mistake to make is on DH

Yes and no. Certain algorithms make it harder to do timing-resistant implementations, but by no means impossible. Probably the easiest mistake to make is on DH/RSA exponentiation. Using the simple square-and-multiply algorithm gives away plenty of timing data; you usually need to explicitly protect against it by either using blinding or always performing both the square and multiply at each iteration.