When I go to the key store folder via Mist I find a .json-file (doesn't have a .json extension, but I believe this is still a .json file) that corresponds with my ether address (UTC blablabla). If I'm correct this file is the encrypted (or password protected) version of my private key.
Now I've got two questions:
Does a (password protected .json file) private key ever change? Is the key the same when it is freshly created as it is after 100 transactions? Meaning: will it suffice if I just back it up after creation?
If I write down the name of the file in the key folder, can I later restore my wallet? Like a cold/paper wallet. Somehow it seems to me this is too short/simple to be a complete private key. It's just UTC + a creation date+the address/public key, but other than that very little extra info.