Is it possible that unconfirmed transactions can never be confirmed again?
Yes under certain circumstances a TX can not be confirmed. Lets say you have a TX (A) that has no fee, dust outputs (<600 satoshi) and is badly propagated (not known to many nodes). If you now make another TX (B) that has a at least reasonable fee, no dust outupts, is well propagated and spends the same input(s) as TX A, chances are that B will be confirmed but not A. Thus A can never be confirmed again because its inputs have allready been spend (with the confirmation of B).
May seem like a stupid question but here I go:
No such things... uhm well unless trolling
How exactly does cold storage work? Read a lot about it but don't understand it. How does a paperwallet work? Lets say I have 1 BTC on a paperwallet (how do I get it onto the paperwallet?), how do I redeem that 1 BTC in lets say 2 years?
The basic idea with bitcoin is that you have private keys that allow you spend coins and addresses that allow you to receive coins. But on a technical level you never actually "get" bitcoins, they are allways in the blockchain you only have the private key to "give" them to someone else. A paperwallet or cold storrage uses this fact to secure the private keys offline, where they can not be reached by malware.
A typical paperwallet would be:
- a private key in a format that is "easy" to read for humans (e.g. 5KKGFKMV...)
- the same private key as QR-Code to easily use it with smartphones or similar
- an address that belongs to said key in the same formats
on a piece of paper.
like this:
Note: DO NOT USE THIS! Its private key is compromised. You can make your own on bitaddress.org, but if you actually want to use it. Create it offline. In order to spend the coins I would scan the private key with my phone (IMHO mycelium is a great for that, but most other wallets allow this as well) and spend them entirely. The change (if any) would go to a new paper wallet or to another address on the phone.
Cold storrage usually refers to a computer that is offline. This computer would hold a basic OS (usually Linux, because its free) and a wallet software that manages the private keys. You also need a computer that is online to "watch" your addresses. If you want to spend coins you make a new TX on the online computer (hot wallet), transfer it to the cold storrage (e.g. via USB*), sign it there and bring it back to the hot wallet to broadcast it to the network. There are several setups and wallets for this, armory is probably the most secure and best known. Off the top of my head electrum and bither** allow cold storrage as well.
* This part is where it all can fall aparet. If the USB Stick you use to transfer the TX has some sort of virus that can infect the offline system all that hassle was for nothing.
** its for android, thus youd need an old phone