Where does the huge amount of "" iCloud Keychain items come from and what is their purpose? I just discovered that there is a huge amount (hundreds) of items in my iCloud Keychain that I can not explain. They were all created starting from 7th of January up until 13th January. 



When I right-click them to see detailed information, 
there isn't any information visible. When I click on "access", under access groups "com.apple.security.octagon" shows up. However I couldn't find anything mentioning that particular URL through googling.

Can anyone explain what purpose those keychains items serve and where they come from?
Messages and FaceTime does per device encryption, so these would map to key pairs generated for device to cloud encrypted devices.

The com.apple is simply a naming convention for the subsystem that claims the entry - and not an actual dns name.

I wouldn’t worry about them till you have tens of thousands and you can always sign out of messaging on all your devices and then try and clean things, but in my experience these self regulate and don’t impair performance if you just focus on the items you know and interact with.