Bitcoin Forum

What prevents someone from copying a wallet and having twice as many bitcoins?

I couldnt tell you the technical answer, but it just doesnt work like that. Im sure its been tried and if it had been a success we would all know. btw welcme to the forums.

The money is not stored in your wallet but in the bitcoin blockchain, which says for example that the address 19Qndhcus62ggx2794n has 10BTC
In order to redeem that money, you need to prove you possess the keys associated with the address (kind of a password)
In the wallet file, you only have those keys
So you may copy a thousand times your keys, you would have the same amount of coins because the amount stored in the blockchain wouldn't have changed

The money is not in the wallet. It is in "the cloud". The wallet merely contains the passwords (privkeys) that enable you to spend the money by sending it to someone else's address.

For example, all of my own personal day-to-day wallets (on cellphone, tablet laptop, desktop, and blockchain.info website) contain copies of the very same privkeys. All of them. Thus, I can spend from the same privkeys no matter where I am.

On the other hand, my nest-egg savings privkeys are not loaded into any wallet anywhere. Again, my nest-egg savings are in the cloud, but cannot be spent by anyone. If/when I want to spend money from a nest-egg amount, I shall load its privkey into a wallet (any wallet) and spend them.

when you copy a house key at the hardware store do you have twice as many house's?  The wallet only stores the keys to your Bitcoin.  The record of them exists on the public block chain.  The address you have people send bitcoins to is a public key which has a corresponding private key.  Only the private key can unlock (or claim) the bitcoins and re spend them.  So no actual bitcoins exist in the wallet.

It's (almost) the same reason that duplicating your checkbook or credit card doesn't give you more money.

Thanks guys!