diff --git a/technic_chests/copper_chest.lua b/technic_chests/copper_chest.lua
index fda1db0..6445d46 100644
--- a/technic_chests/copper_chest.lua
+++ b/technic_chests/copper_chest.lua
@@ -18,6 +18,7 @@ minetest.register_craft({
 
 minetest.register_craft({
 	output = 'technic:copper_locked_chest 1',
+	type = "shapeless",
 	recipe = {
 		{'basic_materials:padlock'},
 		{'technic:copper_chest'},
diff --git a/technic_chests/gold_chest.lua b/technic_chests/gold_chest.lua
index 7a50b70..9497646 100644
--- a/technic_chests/gold_chest.lua
+++ b/technic_chests/gold_chest.lua
@@ -29,6 +29,7 @@ end
 
 minetest.register_craft({
 	output = 'technic:gold_locked_chest',
+	type = "shapeless",
 	recipe = {
 		{'basic_materials:padlock'},
 		{'technic:gold_chest'},
diff --git a/technic_chests/iron_chest.lua b/technic_chests/iron_chest.lua
index 237067b..d522240 100644
--- a/technic_chests/iron_chest.lua
+++ b/technic_chests/iron_chest.lua
@@ -25,6 +25,7 @@ minetest.register_craft({
 
 minetest.register_craft({
 	output = 'technic:iron_locked_chest 1',
+	type = "shapeless",
 	recipe = {
 		{'basic_materials:padlock'},
 		{'technic:iron_chest'},
diff --git a/technic_chests/mithril_chest.lua b/technic_chests/mithril_chest.lua
index fb7917a..52c1ad0 100644
--- a/technic_chests/mithril_chest.lua
+++ b/technic_chests/mithril_chest.lua
@@ -20,6 +20,7 @@ end
 
 minetest.register_craft({
 	output = 'technic:mithril_locked_chest 1',
+	type = "shapeless",
 	recipe = {
 		{'basic_materials:padlock'},
 		{'technic:mithril_chest'},
diff --git a/technic_chests/register.lua b/technic_chests/register.lua
index 9fe6749..9cb5ce8 100644
--- a/technic_chests/register.lua
+++ b/technic_chests/register.lua
@@ -171,6 +171,16 @@ local function get_receive_fields(name, data, locked)
 		end
 
 		local page = "main"
+
+		local owner = meta:get_string("owner")
+		if owner ~= "" then
+			-- prevent modification of locked chests
+			if owner ~= sender:get_player_name() then return end
+		elseif not fields.quit then
+			-- prevent modification of protected chests
+			if minetest.is_protected(pos, sender:get_player_name()) then return end
+		end
+
 		if fields.sort or (data.autosort and fields.quit and meta:get_int("autosort") == 1) then
 			sort_inventory(meta:get_inventory())
 		end
diff --git a/technic_chests/silver_chest.lua b/technic_chests/silver_chest.lua
index 4de196d..8bc8423 100644
--- a/technic_chests/silver_chest.lua
+++ b/technic_chests/silver_chest.lua
@@ -20,6 +20,7 @@ end
 
 minetest.register_craft({
 	output = 'technic:silver_locked_chest',
+	type = "shapeless",
 	recipe = {
 		{'basic_materials:padlock'},
 		{'technic:silver_chest'},