When you specify a parameter as attr_encrypted, it doesn't get included in params that get wrapped automatically in controller actions. You have to manually wrap with a line such as:
params[:user][:ssn] = params[:ssn] if params[:ssn] && params[:user]
Is this within the scope of SymmetricEncryption or is it deep within Rails somewhere?
Closing for now since it sounds like it is out of the scope of SymmetricEncryption. Look forward to any merge requests if this is something that SymmetricEncryption can support out of the box