The library doesn't currently support PFX files directly, only RSA with the properly formatted XML or by populating an RSAParameters object. One thing you'd want to be careful of too is making sure your PFX that you're loading only contains the public
key as you don't want to expose the private key.
There are a couple of ways you could go about loading the PFX info. One would be to just serve back the XML from a web service and connect to it with your app. The benefit of this is that you're not storing it as a resource and you can change
or version that key at a later date if you want. The drawback is that you have to have the service and you create an extra dependency on that service, so if that service ever goes down your app may not function properly unless you've accounted for it.
You could also use SQL Compact to store the key. This gives you the benefit of being able to combine methods. You could store the original xml as a resource and push it to the SQL Compact database when your app first runs, or you could pull the
key originally from a web service and store it. I would probably take one of these routes.
Lastly though, what you could do is write an extension to Scrypt that would allow you to process PFX files since the source is available. If you'd like to write something and contribute it I'd be happy to evaluate it and add it to the library, and
give you proper credit as a contributor of course. If you think this is the best route, one thing you might look into is whether you can use a PEM file instead of PFX. PFX is a binary encoded file, while PEM is a base64 encoded certificate file
with markers that would make it much easier to parse.
I'd have to do a lot of digging to find details on the PFX format as I'm not sure how the data is actually stored and what markers they use to separate it.