Bitcoin Forum

If you have anything that you don't understand about Bitcoin, the bitcoin network, how it works, etc, feel free to ask here.

Hi, I ave a newbie question!

I had setup the bitcoinqt client on a mac, but it's a bit eavybfor a laptop, so I have setup a new bitcoinqt clientbon my home desktop which is a bit more substantial but is a windows pc. Question is can i still just move my wallet.dat across and take my coins and keys with me to the pc, or is te mac wallet.dat a different format?

Thanks!

Myrddin

I'm pretty sure the format is the same, but I'd hang on to a backup of the wallet.dat just in case it doesn't open up correctly.

Hi
I am looking at bitcoin.  Learning slowly as I have been reading quite a bit about it.  My question is one of security and safety of the system and an individual's wallet.  My understanding is that if you lost your wallet or the data destroyed, you would lose your money forever.   Is a USB flashdrive susceptible to loss from an EMP attack?  Is the bitcoin service and servers sufficiently redundant around the world such that if there were an EMP attack in say the US and Europe, that the data and service would continue around the world?  I have read that optical storage on a CD drive would survive an EMP attack and thus preserve one's wallet.  Any comments?
thanks
r

why don't you like noobs?  ???  ;D

Uncertain, but it seems likely to me.  If you are really concerned about an EMP, keep most of your bitcoins stored in a paper wallet.  Only keep a few bitcoins in an electronic wallet at any time.

Yes.  There is no "Bitcoin service", and there are no "Bitcoin severs".  The system is completely decentralized and peer-to-peer.  Every person running a full client is maintaining a full copy of every bitcoin transaction that has ever existed as well as validating and relaying all new transactions.  Every miner in the world is confirming and securing transactions.


Possibly.  I'd feel safer with a paper wallet if I was really worried about an EMP attack.

The format is the same, excepting the fact that many Windoze files have an end-of-file discriptor that Mac files generally do not.  Still, this is an expert level activity that should not be attempted without full backups.  You can't do this without understanding the command-line in both systems, and knowing where the wallet.dat file should be found in both cases.

I'm a newbie at bitcoin, but reasonably proficient at windows/dos and macosx. I know the location of the wallet.dat files on both and gave good backups. So will try and see how it goes if the files should be the same.

Thanks!

Myrddin

Most definately, yes.  Unless you happen to have a faraday cage to keep it in.


There would be a temporary disruption, probably delays; but the outright destruction of bitcoin or the blockchain might actually require a Death Star attack or Giant Yellow Construction Spaceships making way for an interstellar bypass.  Even the destruction of the Internet wouldn't likely destroy the blockchain, although it probably might not be of much value after that.  Bitcoin uses the many-copies-keeps-data-safe method to an extreme, but only one complete copy of the blockchain is required to rebuild the network.


Probably, but then how would you read it?  CD's have a limited data lifespan, unless you spend the cash to get archive grade disks and keep them in the refrigerator.  'Bit rot' has a literal meaning with regard to most commercial quality CD-R's

Restarting your bitcoin client with a new wallet.dat will require that you start the client with the -rescan command line switch, in order to force the client to destroy the database and rebuild it from the beginning of the blockchain.

-rescan.

Fab thanks!

Hi. Since goggling or reading the wiki page about bitcoins doesn't exactly help my situation answer me this:
What is the fastest, easiest and most reliable way in your opinion to buy bitcoins?
I am in the EU(not uk) and we use euros as currency.
Moneygram and Western Union services are available here.

I have had good result with Neteller and Ukash, works well for Europe. I am located in Canada and sell BTC to European clients. My advise - stay away from Paypal, you are liable to get scammed very easy.

You may want to look into localbitcoins.com

If you are lucky, you might find someone local who is as interested in finding a fast, easy, reliable way of selling bitcoins as you are in buying them.

How does the bitcoin-client find the next peers to connect to?

There are several ways, actually.  Upon first boot, the client will depend upon an internal list of 'persistant' nodes that accept all  connections, and then it can receive the addresses of new nodes across the p2p connection itself that the first node is aware of.  On later boots, it remembers who it's been connected to in the past an randomly attempts to reconnect.  You can also specify particular nodes to connect to, if you know their address.

Sometime ago I purchased Bit coin through GetBitcoin LLC. I didn't know what I was doing and somehow made the purchase without an address to send the bitcoin to. I was told the bitcoin was sent and given tracking information through blockexplorer.com I am trying to deposit bitcoin into an account, but I'm not sure how to access my bitcoin. When I click on the link for the order in my email from GetBitcoin (sent 8/6/12) I get request not found. I have emailed GetBitcoin LLC and I get an email back saying they are out of business. I asked walletbit and was given the impression that blockchain.org might know something about it, but they told me they don't provide support for third party services (I thought they were affiliated with blockexplorer). Is it possible with the information that I have from blockexplorer to access the bitcoin to deposit it (it shows an adress...but it shows lots of different ones  :)) ? There is a lot of info sent to me about a completed transaction from blockexplorer.com.....can I use this info to make a deposit?
Moral of my story: learn then go not go then learn ;D

Thanks

I'm not sure how to get your coin back but for next time.

See http://howtobitcoin.blogspot.com/2012/01/how-to-create-bitcoin-wallet-in-3.html for how to create a simple, unsecure bitcoin wallet (good for small amounts of money).

I'll post about paper wallets in a bit for a more secure solution.

So let me see if I have this straight...

• Quite a while back, you purchased bitcoins from a company that now no longer exists (GetBitcoin LLC).
• They claim to have sent bitcoins somewhere, but you have no idea where.
• You didn't have a bitcoin wallet of any sort at the time.
• You still don't have a bitcoin wallet of any sort.
• You have a list of addresses from the transaction as seen in blockexplorer.com
• You want to know if you can gain access to the bitcoins associated with the transaction?

Unless you can find a person who has access to the private keys associated with the addresses that the coins were sent to, I'm sorry to say that those bitcoins can probably be considered gone forever.

I'm not sure exactly what WalletBit or blockchain.org (is that even a website?) have to do with any of this.

There is a public record of every bitcoin transaction that ever occurs.  These transactions are all stored in the Blockchain that every full node maintains a copy of.
All Blockexplorer is doing is showing you this public record in an easy to read format.  They don't actually have access to any of those bitcoins.

Now you state that "There is a lot of info sent to me about a completed transaction".  I'm not sure what you mean by "a lot of information", and I don't know much about how GetBitcoin handled situations where someone purchases bitcoins without providing a bitcoin address.  I suppose if they loaded up an address with bitcoins and then sent you the private key, then you could still access the bitcoins, so if there happens to be a private key in that "lots of information", then you can still gain access to the bitcoins.

I know we can buy physical bitcoins in the U.S. and some other places.  Can we buy physical bitcoins in Canada yet?

you're going to have to post this one in the electrum thread.

hi there. could someone please point me to where i can learn about how the points and shares work on bitcoin.cz  i'm a little confused because sometimes my score and shares reset, sometimes my score will reset and i will still have a lot of shares or vise/versa, i am not losing connection either!

very wise to submit ur SESSID...

I have some questions that have to do with how new blocks are created and how the total number of bitcoins is ultimately limited to 21 million. I vaguely understand that new blocks are created through "solving a cryptographic problem" and that this takes an immense amount of computing power. But what I don't understand is what the cryptographic problem they solve is or how it was made part of the blockchain.

How exactly do the blocks fit together?

What is the information that is analyzed in order to create new blocks and how are they validated to become part of the blockchain? What are blocks checked against to know they are valid?

Could the entire 21 million BTC blockchain technically be solved only from information that was in the very first block or whatever algorithm is used for BTC? Would it be possible (in theory) for all of the information to be known by the creator/Satoshi by having a private key or something that forms the basis for the blockchain?

Wow, you don't ask for much, do you.  This is a huge topic.  Please start by reading the whitepaper...

http://bitcoin.org/bitcoin.pdf

And come back with more specific questions....


No.


No.

Are bitcoins sent to a relaying address before they arrive? I've been trying to get my $500 worth of bitcoins for the last three weeks now. Yankee got the point of sending the amount of bitcoins, but as of now they're sitting in this address  http://blockchain.info/address/1NExi4V2xWoLBmbtDMgKWwPaTb49yMfcTG

Will this eventually get sent to my personal wallet? I did a moneygram order at my local walmart and something messed up with duplicate orders. The correct amount is in that account, but it's not mine. It's been a few hours now since it was sent, and just curious to know IF it's going to be sent.

Also it's at 50 confirmations right now? Is there a limit before its sent?

Haha I thought it might be a tall order!

Thanks for the link - I'll check out the white paper. :)

Lots of questions there, I'll try and break it down into pieces.

The enitre system is peer-to-peer.  So everyone runs a client program that verifies that all the information it receives matches the rules of the protocol, and refuses to forward any information to anyone else if the information isn't valid.  This means that a single person (or group of people) can't add false information into the system because it won't get relayed.
 
Satoshi started the block reward (given to the miners for "solving a block") at 50 BTC.  The protocol that every client uses makes sure that the block reward is cut in half every 210,000 blocks.  If you add up all the bitcoins that can be created as the reward gets smaller and smaller, you'll find that it will never exceed 21 million.

The miners gather up all the unconfirmed transactions that they want to include in a block. They package these together along with some headers and other useful information.  Then they calculate a 256 bit hash (SHA256).  This is actually a VERY fast and VERY easy (for a computer) thing to calculate. This hash has essentially a random numeric value between 0 and 1.158e+77 (a very big number).  The "difficulty" set by the protocol is a target number that the hash has to be less than.  If the hash isn't small enough, then the miner increments a value in the block called a nonce by 1 and recalculates the hash.  The miner repeats this process until the generated hash is small enough.  Due to the difficulty it can take on average about 13,200,000,000,000,000 hash calculations (today with the current difficulty) to find one that is lower than the target.  This takes about 10 minutes for some miner somewhere on the network to happen across.  One reason that a hash is so useful is that when the block is solved and published to the connected peers (and then relayed throughout the network) it is very fast and easy for each node to recalculate the hash with the given nonce to verify that it is the correct hash and that the value is low enough.  Another reason that the hash is so useful is that there is no known way to predict what the hash value is without calculating it.  There is now way to know what nonce will give you a low enough hash without trying each one.


Once a miner solves a block, they tell all the connected peers.  Those peers just validate that the block meets all the rules of the protocol, append the block to the end of the blockchain file that they have, and then relay it on to all the peers that they are connected to.  Those peers do the same, and so on until every node has an updated blockchain.

Each new block is appended to the end of the blockchain file.  I mentioned earlier that each block has some other "useful information", one of those pieces of information is the hash of the previous block.  This means that the client can keep track of the "chain" by comparing the hash stored in each new block with the hash value of the previous block.  It also means that nobody can change any value at all in any earlier block (and convince the entire network that their new value is valid) without first recalculating hashes of enough difficulty of all the blocks that have come since then.  Since the "valid" blockchain is still being updated by the rest of the network you'd be chasing a moving target and have to have more hashing power than all of the bitcoin miners in the whole world combined to be able to regenerate blocks faster than they are generating new ones.


Each unconfirmed transaction that a miner wants to include in a block is analyzed to make sure that it meets the requirements of the protocol, the nonce is incremented, and hashes are calculated and compared to the current network difficulty.

Blocks are checked for valid transactions, headers, and hashes.  (Valid meaning meeting the requirements of the protocol)

No.  The blockchain contains all the bitcoin transactions that have ever occurred.  You'd have to have a list of those transactions and which block each was in to re-create the blockchain.  Even then, since the hashes are essentially random, your re-created blockchain wouldn't match the current one.

The transactions and the protocol are the basis of the blockchain.  It is not possible to know in advance what value to use for the hash.  The only way to figure that out is to iterate through the nonce and keep trying.

Try asking your question in the official BitInstant support thread.  It will likely be seen (and answered) by someone from BitInstant faster that way.

Here is a link to the support thread:

https://bitcointalk.org/index.php?topic=128314.0

It's pretty much resolved to this point other than this hiccup. I've exchanged private messages with Yankee already.

for there to be an EMP attack... there would be war, as a result the internet would be shut down, also in you little mad max fantasy, imagine going to "Bartertown"  the guy says "how are you going to pay?", in the end you find out there are only two ways to pay in such an environment

1. Gold.
2. Services. (you have to sell your ass to a couple of convicts)

and NO a usbflash drive would NOT survive an EMP attack, the usb connectors would act as a high-band arial as would the bonding wires inside the Nand-flash chip package, the resulting charges would bit flip your nand-flash memory cells, since they are a function of charge level stored on a very high impedance gate.

What about devices and networks not effected by the EMP?

Given the scenario described, I doubt many people will be interested in gold in the early years of bartering.  I suspect the only items of value will be those needed for survival: Food, fresh water, weapons, ammunition, and maybe building supplies.

Depends how the front end is protected and the device shielded, but it matters fuck all, if the local ISP/telicom operators shit is fried.
But it is still going to be  a "get ur ass out down in bartertown" scenario, because it is unlikely that the other traders would give a shit about 'bitcoin', even though the majority of survivors WOULD be past bit-coin business men/traders etc.

Only need to look at the run-up to the last world war and events after it to see the pattern, wasn't much call for "building supplies" until WAY after, same with ammo & weapons.