How offline paper-wallet works??

[howard.ashoul]

I downloaded offline paper wallet generator to my PC (for PIVX coin from Github https://github.com/PIVX-Project/PIVX-Paperwallet). I opened .html file in my browser. And it generated my public address and my private key.

So far so good.

But I don't understand how it works? How will network know, that I claimed this address with this private key? Can't somebody else claim the same address? Or did this generator send this info into network behind my back and claimed it?

[1714794796]

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[1714794796]

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[1714794796]

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[1714794796]

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[eXpl0sive]

The network doesn't need to know. Network doesn't keep track of which address is in use and which isn't. The network will never know that this address is in use by someone, until you send some BTC to it.

(Actually, all public/private addresses that can ever exist are theoretically already in place; you're just claiming one by generating the corresponding private key.)

[howard.ashoul]

The network doesn't need to know. Network doesn't keep track of which address is in use and which isn't. The network will never know that this address is in use by someone, until you send some BTC to it.

(Actually, all public/private addresses that can ever exist are theoretically already in place; you're just claiming one by generating the corresponding private key.)

But what keeps you from generating private key for my address?

Network doesn't know, that I generated private key for this address. Your computer doesn't know, that I generated private key for this address. Only my computer knows it.

Why you can't come right now and claim this address, if nobody knows, that I just claimed it?

[eXpl0sive]

The network doesn't need to know. Network doesn't keep track of which address is in use and which isn't. The network will never know that this address is in use by someone, until you send some BTC to it.

(Actually, all public/private addresses that can ever exist are theoretically already in place; you're just claiming one by generating the corresponding private key.)

But what keeps you from generating private key for my address?

Network doesn't know, that I generated private key for this address. Your computer doesn't know, that I generated private key for this address. Only my computer knows it.

Why you can't come right now and claim this address, if nobody knows, that I just claimed it?

Nothing is preventing anyone from accidentally generating the same private key as yours. But the amount of possible private keys is so enormous that there is almost zero chance that two people will ever generate the same key.

Read more:
https://bitcoin.stackexchange.com/questions/7724/what-happens-if-your-bitcoin-client-generates-an-address-identical-to-another-pe

[aplistir]

Well, actually anyone CAN claim your address, if they happen to guess (or generate) the same address that you have.

The only thing is that it is extremely unlikely, because there are so many possible addresses.

If you are scared that someone else could accidentally find your address you could make your wallet a multisig wallet, where no-one can spend the bitcoins if they do not know all keys.

[eXpl0sive]

Read:
https://en.bitcoin.it/wiki/Technical_background_of_version_1_Bitcoin_addresses

"Since Bitcoin addresses are basically random numbers, it is possible, although extremely unlikely, for two people to independently generate the same address. This is called a collision. If this happens, then both the original owner of the address and the colliding owner could spend money sent to that address. It would not be possible for the colliding person to spend the original owner's entire wallet (or vice versa). If you were to intentionally try to make a collision, it would currently take 2^107 times longer to generate a colliding Bitcoin address than to generate a block. As long as the signing and hashing algorithms remain cryptographically strong, it will likely always be more profitable to collect generations and transaction fees than to try to create collisions."

From the other link I posted:
"There is also a chance for your computer to catch on fire, and some of the materials to melt together into a lotto coupon with winning numbers on (and a valid barcode), but it just won't happen because of the chance is so unbelievably small (it's the same with the "click and generate another persons bitcoin address")."

[howard.ashoul]

Thank you. I just read posted links and now I understand it.

I didn't understand how is to possible not to generate same address.

Information, that it is actually possible, but highly unlikely, explains it all to me.

[TryNinja]

Thank you. I just read posted links and now I understand it.

I didn't understand how is to possible not to generate same address.

Information, that it is actually possible, but highly unlikely, explains it all to me.

It's not impossible. But it's also extremely unlikely to happen.
The odds in colliding with a specific address is 1 in 2^160.

If there are a billion users and each have one million active addresses (1 quadrillion funded addresses in the blockchain) the odds in colliding with any address would be roughly 1 in 2^110 (1*10^33).

Vanitygen can produce 20 million keypairs per second.  Lets say you build a super ASIC on 12nm (4 generations ahead of current tech) process that could create, validate, and steal one trillion keypairs per second (1 TK/s). That would be about 50,000x more powerful than faster GPU today.  Lets also say you built a thousand of them and ran them continually with no downtime 24/7/365.   In 1 year you could brute force 3*10^28 possible addresses.  

If there are 1 quadrillion funded addresses you would still have a ~1% chance of colliding with a random funded address in the next 1,000 years.

Source: https://bitcointalk.org/index.php?topic=104461.msg1143828#msg1143828

[maeusi]

That is really interesting. But there is one question. I can generate a private key offline. But how is working reserving a bitcoin adress? Needn't we to be online for that?

[TryNinja]

That is really interesting. But there is one question. I can generate a private key offline. But how is working reserving a bitcoin adress? Needn't we to be online for that?

Not sure if I should waste my time answering you since you seem to be one of those guys who just jump from post to post making random pointless questions. I don't even think you are coming back to read my answer; but anyway...

A paper wallet is just a private key that has the right to spend the coins received by its respective address. You don't need access to the internet while generating a private key because the software already knows that this private keys belongs to X address. When this address receives some Bitcoin, its transaction will be kept registered in the Blockchain, proving that you indeed has those coins, and allowing a "spent" transaction to be made by you in the future.

[supermario64]

That is really interesting. But there is one question. I can generate a private key offline. But how is working reserving a bitcoin adress? Needn't we to be online for that?

Not sure if I should waste my time answering you since you seem to be one of those guys who just jump from post to post making random pointless questions. I don't even think you are coming back to read my answer; but anyway...

A paper wallet is just a private key that has the right to spend the coins received by its respective address. You don't need access to the internet while generating a private key because the software already knows that this private keys belongs to X address. When this address receives some Bitcoin, its transaction will be kept registered in the Blockchain, proving that you indeed has those coins, and allowing a "spent" transaction to be made by you in the future.

I had no problem moving BTC to a paper wallet, but had some trouble finding a place to bring it out from the paper wallet. None of the major online services assist with that kind of thing - had to download some software (which I'm blanking on now).

Any suggestions?

[TryNinja]

I had no problem moving BTC to a paper wallet, but had some trouble finding a place to bring it out from the paper wallet. None of the major online services assist with that kind of thing - had to download some software (which I'm blanking on now).

Any suggestions?

The best option which brings a little of convenience and safety, would be using a safe mobile wallet like Electrum or Mycelium. The whole idea of a paper wallet would be a long term storage and unique usage. When you want to spend those coins, use your phone with Electrum/Mycelium to scan the QR code from the paper wallet (if you have one), and send all your coins to a new wallet.

Other options that does not require an android phone would be: sweep/import your private key by manually typing it (in case is just the private key without any QR code) on a safe wallet (e.g: Electrum for PC) and send all the coins to a new wallet.

If you don't want to download any extra software, you could also use Blockchain.info wallet (which does not have fully control your private keys) to import your paper wallet the same way as described above.