Keys are a form of in-game currency alongside Salvage and CODPoints in Call of Duty: Infinite Warfare. They are very similar to Cryptokeys from Call of Duty: Black Ops III and Depot Credits from Call of Duty: Modern Warfare Remastered. They can be used to open Common or Rare Supply Drop crates and Zombie crates when traded for such items at the Quartermaster.
To open a common Supply Drop or Zombie Crate, it costs 10 keys. To open a Rare Supply Drop or Zombie Crate, it costs 30 keys.
Keys are given an Epic quality when receiving from special event cases, due to their ability to open more cases.
For the 12 Days of Winter event, bundles of 20 keys and 40 keys were given for free on Day 2 and Day 7 of the event, respectively.