I don't understand your stance. You seem to be claiming that the ability to determine whether a number is prime or not is extremely difficult and that it would

I don't understand your stance. You seem to be claiming that the ability to determine whether a number is prime or not is extremely difficult and that it would break (some) cryptography if it were no so. My stance is that (some) cryptography would not be broken unless factorisation of large numbers into two large primes becomes easy. Can you clarify how you think that some cryptography is broken by a relatively simple test of whether a large number is prime or not?