Bitcoin-qt bug?

[eugene64]

Hi, this could be probably a noob question, but i failed to find an answer yet.

I'm using bitcoin-qt 0.7.1-beta (windows)

So, I've made a bet on satoshidice.com (<52000), but no response followed (neither win or lose).
I searched for my bet in "recent" and have found it winning, but the receiving address was none of addresses of my wallet!
I've opened details of the bet and have found my Tx ID, but with some unknown receiving address.
Blockchain.info confirms the same.

So I tried to sent different (less) amount of bitcoins to another dice address. Everything was ok.
Than again tried with 52000-bet and got the same result: some unknown address appeared as a receiving.

Could someone explain the total outcome:
1) I have betting transactions in my wallet history
2) Bitcoins have been spent
3) blockchain.info doesn't show any of my wallet addresses in details to those transactions.
4) Probably winning coins went to some unknown addresses.

[DannyHamilton]

The Bitcoin-Qt wallet does not show you all of your addresses.  It hides some of them (the "change" addresses) from you.

When you spend a bitcoin output, you have to spend the entire output. The protocol makes it impossible to only partially spend a previous output.

So to deal with this, when you create a transaction the Bitcoin-Qt client gathers up as inputs enough previously received outputs to exceed the amount you want the transaction to be.  It then creates two outputs for the transaction.  It creates an output to the address that you are trying to send bitcoins to for the exact amount you are trying to send.  It also creates a new address (commonly called a "change" address) that it keeps track of in your wallet without showing to you in the user interface.  It creates an output in the same transaction using this new address to send the extra value to.

Later when you try to send bitcoins again, Bitcoin-Qt may choose to use the output from this newly created "change" as an input for the transaction.  Satoshi Dice sees this address in the inputs and realizes that it is one of the addresses in your wallet (even if you don't realize it).  It sends the bitcoins to an address from the inputs (which might have been a previous "change" address).  This is ok. Even if you are not familiar with the address, Bitcoin-Qt still knows about it and will include any bitcoins associated with the address when it shows you your balance.

[eugene64]

Thanks for great explanation!
I didn't know that.
And I just recently noticed that sometimes satoshidice shows my main address and sometimes some "random" addresses.
And I've received my winnings, after a while though (seems to be some problems on server side)