Bitcoin Forum

If I have multiple computers and want to track coins in my wallet is this code all I need?

1DdsWtwaNP5iSfKXzwqFYVF4EBoEuiptft

That's for an MTGOX account but im seriously considering using a wallet on my laptop, can I use the same code above for all of my wallets or does each download of the wallet software give me a unique code to use that can only be used with that specific install?

I guess what im asking is, can I use 1 code like above across multiple wallets?

yeah when you start up your local wallet, you get another unique address and an option to create many more.

What if I have a local wallet downloaded on several computers? Laptop, desktop, work pc, etc?

I have only used the online ones so far like mtgox and btce so these download ones are kind of new to me.

What you have there is a public Bitcoin address.  This is used for sending Bitcoins to that address.  In order to use the Bitcoins, you need the private key for this address.  It's really best not to even re-use Bitcoin addresses, though you can technically.  So, the answer to your question is "no".

Okay so basically I setup 1 wallet and just use that, make sure its securer than the Bank of England and hope the private key doesn't get lost, stolen, etc?

Can you , and if so is safe to just leave in mtgox account?

1DdsWtwaNP5iSfKXzwqFYVF4EBoEuiptft - if that code is given to you by mtgox it is not your address. You can't control it from your computer. It is just a token for receiving  payments to mtgox made by you. You can technically pay from mtgox to someone, but the money will come from different address and I'm not sure if sending btc to a third party is allowed in their ToS.

Don't try to synchronize your wallets across computers unless you absolutely know what you are doing.
Original bitcoin-qt client sends leftover coins to a new address every time. Which is counterintuitive and you can end up loosing your coins.

You can setup a shared public address across your computers and after each transaction send any remaining coins (your "cange") back to your public address after transaction (you don't need to wait for 6 confirmations to do so). Or I believe there should be a client which does this automatically in a same transaction. That way you will have the same amount of money on all machines.
To do that start with a fresh new wallet.dat file and request a new address for new account.
Close client. Copy wallet.dat to other computers. After receiving  coins to that address all your computers should see the same amount of btc.
 

Online wallet is the most convenient but least safe method of storing coins. Companies behind them are not as reputable as the banks, and since btc are commonly "virtual commodity for geeks" company have little legal responsibility for "loosing" them.
I personally would not hold there more than 1btc for a quick trade.

I would also be quite careful having your wallet on multiple machines.

This needs to be in a FAQ somewhere.

If you think you'll want/need to access your bitcoin wallet from multiple computers/devices, look into https://blockchain.info/wallet.  With this online wallet you have access to all your private keys and as such you'll be able to maintain control of your bitcoins (make sure you get a backup from the website).  Your private keys are stored encrypted in their database so they don't have access to take/spend your bitcoins.

A
their database... I bet encryption is done by them too  :D

B

I don't get it. For me B contradicts A.
How do you pay from your online wallet if they don't have access to it.

just see!

If you want just to track coins in your wallet, check it on blockchain.info Wallet can be offline. You need to bring it online only when you need to spend money from it.

The code is open source, and has been reviewed by others.  If you know javascript you are welcome to review the code yourself to confirm that is behaves as advertized.

B does not contradict A.  A is the reason that B is true.

The encryption is done with javascript by your browser on your machine.  They send the encrypted private key to your browser, your browser uses your password (which it does not supply to blockchain.info) to decrypt the private key so that the transaction can be signed.  Your browser then sends the signed transaction back up to their servers to be broadcast.

Since they don't have your password, and they only have the encrypted copies of your private keys, they cannot take/spend your bitcoins.

Of course, that means that if you forget your password, they can't help you.  Your coins are just as lost as if you had forgotten your password to an encrypted wallet file on your own hard drive.

Private keys and bitcoin addresses are generated with javascript and only sent to their database after being encrypted by the password stored in your browser.  You can have a copy of your encrypted wallet from their database sent to you so that you can store backup copies and still access your bitcoins if blockchain.info were to be shut down.

You can also create as many addresses as you need for different purposes.

one

Thank you for clarification. The security seems reasonable to me now.