Fastest primality test

Question

Could you suggest a fast, deterministic method that is usable in practice, for testing if a large number is prime or not?

Also, I would like to know how to use no

Answer 1

If you're looking to find a random prime for use in RSA keys, you should use a probabilistic test initially. If the probability is high enough for your needs then stop there. If you must be certain, then once you find a large random probable-prime, verify it with AKS or another non-probabilistic test. This lets you check a lot of non-primes quickly while being certain when you think you've found one.

If you're trying to verify a specific existing number is prime then you should use one of the tests that answers with certainty. There are other non-polynomial-time tests too, use the one that is fastest in practice.