Storing and segregating Bitcoins

[Lina.V]

I recently purchased some Bitcoins as a speculative investment. I then bought a USB stick, made an encrypted folder on it and backup my wallet.dat file there.

My problem is that now I want to buy more BTC for some purchases, but I don’t want to spend the bitcoins that I previously purchased. I think what I have is just the standard Bitcoin wallet on my PC. Can I choose which bitcoins that I spend, so that I don’t use the bitcoins that I have backup on my USB stick?? 

Advice and suggestions appreciated,
Thanks!

[Gabi]

The coins that the standard client shows are the one in the wallet.dat file inside appdata/bitcoin

If you want to have another wallet.dat you must first remove that one, so the client will create a new one. MAKE SURE YOU HAVE A BACKUP OF IT! Yes, you said you backuped on the USB stick, it's fine, just make sure you never lose it!

[DannyHamilton]

With the standard bitcoin client, you do not get to choose which bitcoins are spent from the wallet.  You might want to look into using something like blockchain.info online wallet for your spending account.  If you really want to use the reference client for the bitcoins you are going to spend, you can swap wallet.dat files, but you have to be extremely careful and be sure that you know exactly what you are doing.  If you accidentally lose track of which wallet.dat file is which and when it was last backed up, you can end up permanently losing access to your bitcoins.

[Yuhfhrh]

What I do is send all of my bitcoins I want to move to savings into a specific address that isn't even on my wallet. If I'm understanding this correctly, the wallet.dat file on the USB stick is just a backup of the one currently on your computer's bitcoin wallet, so here's what I would do:

1. Make another backup of your current wallet.dat
2. Open the bitcoin wallet, and create a new receiving address.
3. Send all the bitcoins you want to save to that address.
4. Go to help->debug->console
5. Type, dumpprivkey <address from step 2>
6. Keep that private key on your usb stick instead of the wallet.dat
7. Go to appdata/bitcoin and restore your wallet.dat from step 1.

Now you have:
A Bitcoin wallet on computer for general bitcoin transactions, and a separate address not part of your wallet to send bitcoin savings. To spend the coins from the saving address, simply go to help->debug->console and type importprivkey <private key from step 5>

But that's just me. 

[nobbynobbynoob]

Yes, I've done that as well, made an offline wallet with the private keys stored in 51-character WIF in a text file that is stored in a TrueCrypt. However, I hashed up the keys on an offline computer to keep them away from possible malware (even though I'm reasonably confident my main Winbloze system isn't compromised, it can't hurt to be too careful).

[marnie]

Question, what does wallet.dat look like?
I mean if I named it joe.txt could someone open it and know it's a wallet?

[Foxpup]

Question, what does wallet.dat look like?
I mean if I named it joe.txt could someone open it and know it's a wallet?

It looks like a Berkeley database file (because that's what it is), and renaming it won't fool anyone (which is to be expected, since renaming files never fools anyone). You should be using encryption to hide things you want hidden, not some stupid trick like this. Note that Bitcoin's built-in wallet encryption only encrypts the wallet's private keys (preventing anyone from spending your coins without the passphrase), it does not hide the fact that it is a wallet or even your public addresses. Encrypt your wallet again with another program (such as TrueCrypt) if you want to hide it.