For example, users that want to sign all outgoing messages by default
can set:
	:crypto_default: :sign
in ~/.sup/config.yaml. Configuring an invalid value will cause a list
of the valid values to be logged at the "error" level.
     @selection = 0
   end
 
-  def set_to val; @selection = @vals.index(val) end
+  def set_to val
+    if @vals.index(val)
+      @selection = @vals.index(val)
+    else
+      error "Invalid option ", val.inspect, " (valid options: ", @vals.inspect, ")"
+    end
+  end
 
   def val; @vals[@selection] end
 
 
       if CryptoManager.have_crypto?
         HorizontalSelector.new "Crypto:", [:none] + CryptoManager::OUTGOING_MESSAGE_OPERATIONS.keys, ["None"] + CryptoManager::OUTGOING_MESSAGE_OPERATIONS.values
       end
-    add_selector @crypto_selector if @crypto_selector
+    if @crypto_selector
+      if !$config[:crypto_default].nil?
+        @crypto_selector.set_to $config[:crypto_default]
+      end
+      add_selector @crypto_selector
+    end
     
     HookManager.run "before-edit", :header => @header, :body => @body