A weak but tenacious code gate for Weyland! I've seen a lot of this due to rampaging Hippos and hungry Maxxes with Spoons destroying ice left and right, because this can't ever fall prey to those if it's correctly placed on HQ. Anywhere else and this is diet Enigma, so please don't do that.
This one REALLY hoses Anarchs running Black Orchestra (aka all of them), they pay 3 to break and still have to hit the first sub to even get a look at HQ. It's a minimum cost 3 for pretty much every Decoder, which is solid for a 3 cost ETR. It slots in just about any Weyland deck that wants to discourage frequent HQ runs!