Keys (including key rings) are newbiefied - even if you death cry and lose all your stuff, your keys will always stay with you as long as you keep them at the top of your pack (like your safety box).
Anyone can copy a key, either bought from a provisioner or made by a tinker. To copy a key, simply double-click the blank key and target the key you want to copy. No skill required! Keys can be named (or renamed) by double-clicking the key then targeting the key itself. To add a key to a key ring, double-click the key ring and target the key that you want to add. To remove all the keys from the key ring, double-click the key ring and target the key ring.
You can't use a key to lock a container if the key is inside of the container that is being locked.