When I use InstaWallet.org, do I get my own Bitcoin address?

InstaWallet is an online Bitcoin wallet service. When I visit it for the first time, it generates a Bitcoin address that I can use to deposit to.

I’m wondering whether that address is only ever used for my account, or whether all the coins that InstaWallet receive end up in a single large wallet.

  • If it’s only ever used for my account, I should be able to use blockexplorer to monitor my balance. That’s the case with MyWallet, since they don’t even have access to the address’ private key.
  • On the other hand, if everything goes into a single wallet, it’s possible that other users’ withdrawals may be paid with funds from my deposit address. That’s what happens at MtGox and other exchanges.

So which is it?

Are there Bitcoin password crackers I can use to recover forgotten passwords?

I’ve lost the password to one of my wallets (it’s a small one, don’t worry). I was sure I remembered the password … but evidently I don’t.

Is there a program that I can use to brute-force my password, given hints?

Meaning, suppose that I remember that my password was “abc”, but in fact maybe it’s “Abc” or “Abc0”. I would give the cracker program the string “abc” as a hint, and it would try a lot of permutations on it until it finds the real password.

Does such a cracker program currently exist? (Reliable sources please, hopefully open source)

When does the main client relay its knowledge of TXs in INV message?

The inv message is used to relay one’s knowledge of blocks and txs to other clients in the Network. When a new Client connects to the Network, it first receives information about all the blocks in form of an inv message, as a response to getblocks messages. As there is no gettx message, I presume the information about transactions is relayed in the last inv response to getblocks. Is that indeed the way the Standard Client operates, or does it just relay the tx messages only when they arrive, making newly connected Clients wait to catch up with the information about the txs?

Transaction signature generation

When one sets up a transaction, the input of the transaction needs to have a script with a signature to show that you can spend those coins. Which fields of the previous and current transactions need to be concatenated into a message and signed to generate a proper signature? Can someone provide some examples?