Accounting (not legal one) of bitcons...

[dE_logics]

Suppose I've some Bitcoins in my wallet, and I restart my client which will generate a new address, and then make a transaction.

How will I prove to the network, that the coins owned by me are genuinely owned by me and not fake? Cause the address has changed, where's the proof that I genuinely own the bitcoins?

Should I keep my wallet up all the time? If so, what if I change addresses?

[superduh]

restarting wallet shouldn't generate a new address - unless i'm mistaken

[kjj]

You have lots of keys, and they are intended to be used at most one time each.  What is shown to you is (the address that corresponds to) a new key that hasn't ever been used.

[DannyHamilton]

Suppose I've some Bitcoins in my wallet, and I restart my client which will generate a new address, and then make a transaction.

How will I prove to the network, that the coins owned by me are genuinely owned by me and not fake? Cause the address has changed, where's the proof that I genuinely own the bitcoins?

Should I keep my wallet up all the time? If so, what if I change addresses?

Lets start with a simple question.  What wallet are you using?

Each wallet is a bit different from the others.  I'm not aware of any wallet that gives you a new address just from restarting the client, so I can't say for certain what happens when the address changes.

Any well written wallet should keep track of all the addresses that you've received bitcoins at.

[dE_logics]

Suppose I've some Bitcoins in my wallet, and I restart my client which will generate a new address, and then make a transaction.

How will I prove to the network, that the coins owned by me are genuinely owned by me and not fake? Cause the address has changed, where's the proof that I genuinely own the bitcoins?

Should I keep my wallet up all the time? If so, what if I change addresses?

Lets start with a simple question.  What wallet are you using?

Each wallet is a bit different from the others.  I'm not aware of any wallet that gives you a new address just from restarting the client, so I can't say for certain what happens when the address changes.

Any well written wallet should keep track of all the addresses that you've received bitcoins at.

I'm using bitcoin-qt.

So, addresses should not change, and address are the sole means to keep a track of bitcoin accountancy.

So before acquiring an address, does the Bitcoin wallet confirm with the network that there are no duplicated addresses? Or is it that the client completely relies on randomness and probability to generate a unique address each time?

Cause the process of acquiring new address is very frequent in the Bitcoin network. For each transaction, it's recommended to make a new address; considering the no. of transactions, don't you think the possible public/private key pair will exhaust soon, or overtime, the probability of a collision will increase dramatically?

[drawingthesun]

Cause the process of acquiring new address is very frequent in the Bitcoin network. For each transaction, it's recommended to make a new address; considering the no. of transactions, don't you think the possible public/private key pair will exhaust soon, or overtime, the probability of a collision will increase dramatically?

You are right that we reduce the unused address space every time we make a new one, but the space of addresses is so large its not a issue.

I wrote this ages ago about the scale of the address sapce:

Have some fun with this:

http://www.wolframalpha.com/input/?i=1000000*7000000000*365*24*60*60*14000000000*1000000

If 7 billion people were to generate 1 million addresses every second for a million times the age of the universe we would not run out of addresses.

(compare to http://www.wolframalpha.com/input/?i=2%5E160)

Interestingly, every time you create an address you are playing a lottery in which you may win someones coins. The only issue is that this lottery is the most difficult lottery in the cosmos.

[DannyHamilton]

I'm using bitcoin-qt.

So, addresses should not change,

Correct.  You can generate additional addresses, and if you lose your wallet.dat file without a good backup you will lose all your bitcoins forever. As long as you keep a good recent copy of your wallet.dat file, you should continue to have access to the coins that are sent to any address that wallet has ever generated.

and address are the sole means to keep a track of bitcoin accountancy.

That's a good way to think about it, but in reality signatures generated with private keys are the sole means to reassign control of bitcoin value to someone else.

So before acquiring an address, does the Bitcoin wallet confirm with the network that there are no duplicated addresses?

No.

Or is it that the client completely relies on randomness and probability to generate a unique address each time?

Correct.

Cause the process of acquiring new address is very frequent in the Bitcoin network.

Yes.

For each transaction, it's recommended to make a new address;

Yes.

considering the no. of transactions, don't you think the possible public/private key pair will exhaust soon, or overtime, the probability of a collision will increase dramatically?

No.  2¹⁶⁰ is a very very very very big number.  Humans seem to have a very difficult time understanding just how big such a number is.

[dE_logics]

@DannyHamilton

Thanks for the responses! You're a life saver!

I read up more on 'transactions' as stored in blocks and it cleared things up.