Mathematically you do not need to determine primes to brute force break an RSA key...some fast GPUs and you can break some RSA keys daily...all I have to do is

Mathematically you do not need to determine primes to brute force break an RSA key...some fast GPUs and you can break some RSA keys daily...all I have to do is GUESS A PRIME and try it on the resulting encrypted message and measure the result for word and letter frequencies in modern human languages...Scary is it not?