Topic: Get Bitcoin When Client Is closed (Read 600 times)

From Bitcoin Step by Step:

Trading BTC
Let us start with how BTC is exchanged.  In simple terms, the process of sending BTC from one user to another is based on asymmetric cryptography.  This means that if Alice wants to send Bob 12.5 BTC, the following would have to occur:
1.   Bob uses the wallet application to create an address, which is represented by the software as a long string of alphanumeric characters. 
2.   Bob gives Alice the address which is the public key for which Bob has a matching private key in his wallet.
3.   Alice uses her Bitcoin application to send 12.5 BTC to Bob using the provided address.
4.   The transaction is made public on the network and miners begin to process it.
5.   Once the transaction has gone through enough cycles on the network, it is released to Bob.
The 12.5 BTC are now no longer Alice’s.  The 12.5 BTC now belong to Bob.  The information that proves Bob’s ownership exists in the database of blocks which is stored on your local PC by the wallet application or on the online wallet service if you choose an online wallet.  The proof of ownership for Bob is that private key which is stored in his wallet.  The fact that everyone in the network has the same information protects Bob’s right to ownership as long as he retains the secret keys.  He could give someone his wallet, or it could be stolen from him and the bearer would have the ability to take the BTC and transfer them to another account.

I'd quote it, but its my book.

I didn't go into how change is handled, the book was geared for Newbies.

Correct you most definitely do not have to have your computer on.

Similar questions are often asked by new users. Those who explain Bitcoin to others should make this clear early on in the conversation/writeup.

thanks for the answer

No it doesn't need to be open, no there is no time limit (the particular client doesn't matter).  If you have been offline your client will need to update your local copy of the blockchain to be "current" and that may take some time if you have been offline for a while.  Your client needs a current copy of the blockchain in order to "see" coins which have been sent to you.  The client needs to "see" the coins in the block chain in order to update your wallet balance and create the transaction which allows you spend them.  

If you want the more complete answer.  Nobody ever sends Bitcoins TO YOU.  When someone "spends" Bitcoins they announce to the entire  network that change in ownership has occurred.  The network will validate and permanently store that change in ownership until such time as you announce another change in ownership.  Your wallet contains the private keys which ensure you and only you can do that.  If you never come online and spend those coins they will always exist in the blockchain and will never be spent.

Hello.
I'm Using multibit client.
Most Of the Time my computer is closed and Of course also the multibit client.
If someone send me bitcoins, is my client need to be open ?
If not, is there a time limit to open my client which after that I'll lose the bitcoins sent to me ?

Thanks