Can I send from unused addresses?

[rickbee14]

When I send bitcoins, it sends them from addresses I've already received to. I thought it would be possible to send from a new address every time, because the bitcoins are tied to the wallet and not to the individual addresses. Is this not the case?

[achow101]

That is not how Bitcoin works.

On a technical level, there is no such object called a Bitcoin, there are no addresses, and you are not sending to an address. How Bitcoin works is through transaction outputs. Most outputs contain a part of it that can then be encoded as the address that you see, so each output is specifically tied to an address. When you spend, you must spend from previous transaction outputs, and thus you can only spend from addresses which have received Bitcoin.

The network doesn't know about your wallet, nor does it care. All it knows about are transaction outputs. Thus, the Bitcoin is tied to addresses, not wallets.

[rickbee14]

Ah, okay. That makes sense.

Another question: do all the wallets in a single Armory installation use the same private keys for signing transactions, or does each wallet have its own?

[achow101]

Ah, okay. That makes sense.

Another question: do all the wallets in a single Armory installation use the same private keys for signing transactions, or does each wallet have its own?

Neither. Private keys are not associated with wallets, but with addresses. Again, wallets have nothing to do with how Bitcoin works and are completely unrelated. All that matters are the transaction outputs and thus the addresses. Each address must have its own private key as each address is derived from the public key which is derived from a single private key.

[rickbee14]

I understand. So then if I have multiple wallets in Armory, there's no connection in the blockchain if there are no transactions between any of the addresses in those two wallets (even using something like WalletExplorer)?

[achow101]

I understand. So then if I have multiple wallets in Armory, there's no connection in the blockchain if there are no transactions between any of the addresses in those two wallets (even using something like WalletExplorer)?

Yes.

[rickbee14]

Thanks for the info!