Returns values for P and G that are hard coded in this library. Contrary to what your intuition may tell you, using these hard coded values is perfectly safe. The values of the P and G parameters are taken from 'The OAKLEY Key Determination Protocol' [RFC2412]. This is the prefered key generation method, because it is very fast and very safe. Because this method uses fixed values for the P and G parameters, not all bit sizes are supported. The current implementation supports bit sizes of 768, 1024 and 1536.