The use of whisper in pss is a hack, and should be cleanly implemented that limits the components used to components required.

Furthermore, pss should allow for any encryption and key exchange/shared secret scheme.

This process has the following steps:

[ ] - Distill whisper elements in pss to a custom fallback crypto that ideally takes just the elements from the whisper source code that are needed.
[ ] - Define a modular crypto API based on a selection of reference message crypto implementations
[ ] - Implement API
[ ] - Move fallback crypto into separate package, connected to abovementioned API