Coded Chest

A chest similar to the enderchest that uses a gui with several 'dials' (each using the galactic alphabet to keep the theme of minecraft). Every coded chest with the same settings will share inventories, so an adventurer in the end can barter with someone in the overworld for forgotten supplies and use the /tell command to securely share the code for the transfer. To keep the chest from being too overpowered, the chest could be impossible to open, but could be accessed using hoppers/droppers; or a reduced inventory similar to a hopper.

The crafting recipe could be a hopper but with an enderchest instead of the standard chest.