Help With Coding Challenge - Observer/Notfiers in admin?

[Dayo]

I am working on a payment module and got it working.

However, I want to store a password as an encrypted string and cannot figure out at which point I can access the DB after the user clicks "Update" in Admin.

After looking at the flow, I noticed that the Update button triggers the "Save" bit of code in Module.php which then saves the users selection in the DB.

I will like to know if there is anywhere I could then take the field I am interested in after this point and run my encryption and resave.

The encryption and SQL needed is not an issue but just where to put the code to do what I want it to do.

I don't want to edit Module.php which is the only place I can think of at present.

It would be great if there was a call to an "after-save" function in module.php that will allow developers to run code they want.

Notwithstanding this, any ideas how to go about this?

Thanks.