How to reduce factorization into Independent Set Problem? Is it possible to reduce RSA (basically factorization) into a NP-Complete problem, concretely the ISP (Independent Set Problem)?

If so, which as far as I know is possible, how is it done?

I can't imagine how a problem like factorization could be interpreted as a binary symmetric matrix.
IF can be reduced to 3SAT. This was already addressed here before - https://cs.stackexchange.com/questions/11718/generating-3sat-circuit-for-integer-factorization-example

It should easy to convert that 3SAT to ISP - http://www.mi.fu-berlin.de/wiki/pub/ABI/ComputabilityComplexityWS11/Complexity2.pdf