Hi Leslie,
If you are producing your own build from source code I suppose you could change that, but in general I recommend avoid forking the code.
Since I am planning to change to sha512 it might not be a problem except for the fact that I plan to use salt in the hashing as well and that is not currently implemented in the methods available in mojoMembershhipProvider. I'll probably make it check if there is a salt value in the PasswordSalt field and if not then hash without it so it may not pose a problem but it is something to be aware of.
I'm going to have to change the code from using the SiteUser.Login method which just returns the username if the password is correct (as checked in the database after hashing the password and passing it in), and instead bring back the user based on the email or login name if he exists and then validate inside mojoMembershipProvider so that I can pull back the hashed password and the salt with one hit to to db since I can't do the hashing and salting in the database (at least not in all the supported database layers).
But if that is the only change you make it may work out ok to upgrade later where your changes will be lost and mine will replace them, it would just mean that your existing users before upgrading would not have the salt.
Best,
Joe