Therefore, if an 'algorithm that enables prime factorization of a huge number of digits' is developed, its safety will be shaken.

In 1994, American mathematician Peter Shor showed that quantum computers can efficiently run algorithms that will quickly solve prime-number factoring problems.

Having said all of that, your broader point is correct, that it has not been proven that a polynomial time algorithm for prime factorization does not exist. It is thought unlikely to exist, but ...