Those of you familiar with the RSA crypto algorithm will know it boils down to some incredibly simple number theory. ie. Generate two large primes p and q, and compute e and d such that:
n = p.q
e.d =~ 1 (mod n)
All that math is in the patent, and that is the absolute essence of what they are patenting. But they get around this by drawing block diagrams for every possible way to create a communication channel that is encrypted and decrypted using RSA. They then just use the word device in the title, and Bob's your aunty's live in lover.
The whole thing is peverse and absurd. But it's the way it has been for a long time, and this is unlikely to change anything.