Minecraft Modification Lock and Key

My idea is to have a lock and key for chests. The reason is because my friend keeps trying to steal my stuff when we play online in the world he created. Right now, because we play online in his world, he can go into the world anytime and steal my items. To create the key in the crafting table, I would have one gold ingot in the top left corner, one gold ingot in the top right corner, an undropping potion in the top middle spot, one gold ingot in the middle spot in the middle row, one gold ingot on both sides of the middle spot, and one gold ingot below the middle spot.To create the lock in the crafting table, I would have one iron ingot in the top middle spot, one in the left spot in the middle row, one in the right spot in the middle row, one in the middle spot on the bottom row, one on both sides of the middle spot on the bottom row.To create the lockable chest in the crafting table, I would have it be the same recipe as the chest but with an iron nugget in the spot that is empty. To create the undropping potion in the brewing stand, I would have it be an awkward potion in the potion spot with a blaze rod in the spot were you place what you want to have to make a potion. The undropping potion works like this were when you make the key even when keep inventory is off when you die it still won't drop. Also only the person who makes the key can use it. Another thing is I would have a separate slot next to the off hand slot only for the key.