RSA Patent valid?

We were having a discussion in my Computers and Society class about intellectual property, and the professor pointed out that the courts have consistently upheld patents of devices and processes which involve computers, but have shot down patents on algorithms. With that in mind, would the RSA patent stand up in court? Maybe that's why RSA has never sued anyone. They know the patent might not hold up, and it's easier to just keep their licensing fees lower than the cost of a lawsuit. If this is the case, it's good news for cypherpunks, because it means they will never take any action against us.