This might be a very simple question. However, I am just learning the concept, so just excuse me.
I am wondering why there is not any attempt to generate all semiprime numbers? (as an dict. attack to RSA-xxx algorithms). Because as far as I can see, all one is to do is as following:
- get a database of prime numbers
- multiply each prime number with each one. (which will require O(n^2) space)
- save the product.
Of course, you will not do this for all of the prime numbers:)
You will do this to prime numbers which will fall to the domain of RSA's random prime generator. In other words, which will create a $x$-bit number for RSA-$x$ (2048 bit for RSA-2048, for example).
I am sure one of these steps is impractical. Can you tell which one?