The reason i asked this question, because i just discover bitcoin a day back. And i found out that there are 3 type of wallet, which is in web like coinbase, our own computer like multibit, and mobile wallet.
Seems like those 3 have flaw. I just imagine, if my computer got crashed or the website closed; will that mean i lost all the entire bitcoin. Is there any other method to keep bitcoin in the safest place on earth?
Sorry if this sound too noob. Thanks for answering.
The answer from Anton A. is pretty good; I'm adding this as additional information.
Offline wallets are stored on a computer that never connects to the network so they can only be hacked by being physically present. Additional security can be added by encrypting the Bitcoin wallet or the computer as a whole (be aware on the later that the encrypted computer is only secure once it has been completely shut down for several minutes).
The way it works with Armory is that you have an online copy with the public key where you can see your balance. To create a transaction you do it on the online wallet, copy it to a USB stick, connect it to the offline computer and sign it there, then once you load the signed transaction on the online wallet it gets sent to the Bitcoin network for inclusion in blocks.
The paper backup is needed to recover your Bitcoin in case you lose your offline wallet or password (failure, fire, etc.). I recommend storing it in a bank safe if it holds any substantial value.
Another type of wallet that provides a new, handier way of storing Bitcoin safely is called a Hardware wallet. Hardware wallets are a small piece of hardware which store your private key securely and only allow signing transaction, in some case with an address confirmation display and PIN. Just like offline wallets, hardware wallets allow you to save a paper copy of your key in case you lose or break the device.
These devices are safe to use even on a compromised computer provided that you can verify the transaction output addresses before letting the device sign it, and a PIN may protect the device from theft. There are multiple different implementations with varying levels of security. Some of these wallets have additional features such as providing 2-factor authentication.
Offline wallets are probably still the best way to store large amounts securely, accompanied with either a mobile or hardware wallet for day-to-day Bitcoin transactions.
Install Electrum or Armory on an offline computer, create a deterministic wallet, print a paper backup, make a watch-only copy of your wallet & load it to a usb harddrive.
install the same wallet software on an online computer, load the watch-only copy to this software. You're almost entirely safe.
Additionally:
Store your paper backup in a different physical location than the offline computer. Make sure it's safe.
Encrypt the hard disk of your offline computer, never connect it to internet and use strong passwords for users.
Not the simplest of setups but this is the safest option at the moment as far as i know.
The true safest place to hold bitcoins is a paper wallet. However, they are not very convenient for spending the coins in it.
On your concern about computer and online wallets
I just imagine, if my computer got crashed or the website closed; will that mean i lost all the entire bitcoin.
There are plenty of wallets that allow you to make a paper backup of the wallet. I know Armory does this very well, but undoubtedly there are plenty of others out there.
Most wallets, local or shared, allow you to set an encryption key so that your private keys are stored safely. Those wallets will ask you to enter the key when you want to make a transaction. Examples of wallets implementing this are the original Bitcoin-Qt client (when you enable encryption), Armory but also shared wallet Blockchain's My Wallet (when a second password is enabled).
As you say there are many different kinds of crypto wallets. All wallets can be divided into four kinds;
I recommend reading this complete guide about Bitcoin wallets. There you find more info and which hardware wallets that are best. Let me know if you have any questions.
The safest wallet is no wallet at all.
Odd as it might sound, for a cold wallet (aka your big fat BTC account) all you really need and you should have are the private keys of your non-empty accounts and of course your pass-phrase.
Memorize them and no one can steal them from you (except from amnesia).
Store them in an encrypted flash drive in a not-so-obvious format and no one will ever know what they are and what they're for, even if they ever manage to decrypt your flash drive, plus they still need your pass-phrase.
For a hot wallet (every day's stuff) solution, the previous commentators have suggested pretty good solutions.
