text:
Where can I find a worknig fedoracoin wallet for Windows?
I downloaded the fedora coin wallet but when I open the file it says “file incomplete or damaged”. I download it from fedoracoin web site more than ten times with the same outcome.
So where can I download a wallet that will work for Windows 7?

Try to "run as administrator".


text:
Mtgox account verification pending, how to withdraw my bitcoins?
I had submitted my personal document for verification over 30 days; however, my account still pending for verification, what I can do to withdraw my bitcoin?

This is a question probably best asked on the MtGox support site.

Use a different exchange?

all the new accounts created since a few months have to be verified for any withdrawals, including bitcoins, as stated in a big warning on every page of mtgox :
"Attention Users: All withdrawals and deposits require account verification."
so yes you ll have to wait for your verification to be processed before you can withdraw anything.
the delays seem to be around 5-6 weeks, so . ..  if you already waited one month you should soon get an answer, you will  receive an email when your verification is processed.

source: Stack Exchange

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sort: votes


text:
I lost my Bitcoin wallet passhrase. Are my Bitcoins lost?
After reading about all the hacks I created a passphrase that I cant remember.

Are Coins lost forever in the blockchain?
There must be a lot of coins in this state… Is there any way to see what coins are active?
Trying to retrieve these coins via the public key would break the security of the whole network??
If I know 80-90% of what the passphrase is… Is there a piece of software that can brute force attack using my knowledge of the passphrase as a educated library attack??

1 and 3) Yes. 2 and 4) Don't know.

There are various clients that work different ways.  Are you describing the passphrase used for encrypting the bitcoin.org wallet?

Yes it is the passphrase to encrypt the standard client

Related question: http://bitcoin.stackexchange.com/questions/3313/are-there-bitcoin-password-crackers-i-can-use-to-recover-forgotten-passwords

If you have encrypted your Bitcoin.org wallet with a passphrase, then only having that passphrase will allow that to be decrypted.
If you have a backup of your wallet prior to performing the encryption step, then any coins from that wallet that still have not been spent can be recovered.
Otherwise, without that passphase to open the wallet you cant get to the private keys inside the wallet, and thus cannot spend those funds.
There is no difference between "lost coins" and "unspent" coins, so no there are nothing more than anecdotal evidence as to how many coins have been lost.
There are ways to try to recover your wallet based on hints about what you remember about your passphrase.

I supose we could use the librarys/API to write a program

The source is here: http://bitcointalk.org/index.php?topic=85495.msg942171#msg942171   But that is probably not something the typical user would use.  They might use a service that tried to crack it.

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text:
What's the safest way to buy bitcoins in the UK?
I have come across multiple websites offering bitcoins for UK bank transfer. What site have people had the best experience with?
I've come across a few so
www.quickbitcoin.co.uk
www.bitbargain.co.uk
www.blockchain.info
Ideas?

The problem is that there are no real customer satisfaction surveys for exchanges yet, and your question falls into the "recommendation questions can't be factually answered" category. Personally, I have made good experiences with Bitstamp, but who knows. See my answer to a very similar question here: http://bitcoin.stackexchange.com/a/12718/5406

possible duplicate of Best trader from an European perspective

check out Kraken or bitstamp. I know bitstamp accepts SEPA and kraken is very legit.

I am indeed the founder. I asked this a while back to find out people's experiences with other sites and to find a steady supply of bitcoin. It was really hard to know who to trust when we started.

I have purchased from both http://quickbitcoin.co.uk and http://bitbargain.co.uk and have had good experiences with both.
If I had to recommend one, I would go with http://quickbitcoin.co.uk as you are dealing with a company rather than a random individual (which is the case on bitbargain).  I have found that quickbitcoin is very fast, and usually takes 10-15 minutes from sending you money to receiving your coins.

This is great. quickbitcoin takes UK bank transfer. I just tried them and got my coins in about 10 minutes. I figured I didn't want to wait for days for my bitcoins ;)

The safest way (though perhaps not convenient) is to create a two-party legal contract with signed witnesses. This way if either party reneges you have legal recourse in the civil courts. The contractual arrangement would be somewhat similar to when a freelancer charges bitcoins for their goods or services.
Escrow doesn't provide the same level of protection, as your legal contract with the escrow company (if any) usually includes a clause that final binding arbitration is made by the escrow company - not you. However, a reputable escrow service or currency exchange will typically suffice for people with moderate risk appetites.

I've used localbitcoins.com quite a few times with UK bank transfers and haven't been disappointed yet. Transactions have been generally very fast and prices are getting better as the arbitrage opportunities are being soaked up. You should of course follow their safety guidance and if you are nervous then stick to users with high numbers of previous transactions.
I have had funds stuck in exchanges that had their bank accounts closed in the past though. So as the regulatory landscape changes then these kind of companies are carrying some risk, especially in the US where the practice has been freeze assets first, talk later.
Generally if you are only buying then bitcoin are hardly ever 'seized' and it's only if you have fiat funds in someone elses account that you are likely to have a problem.

Yes. I used localbitcoins many times. Make sure you buy from somebody with some reputation already. It uses escrow regulated by the company and is clear on how to use it properly without getting conned.

I'm from the UK and I've had no problems doing the following;

Bank transfer to MtGox
wait 3-4 days until money is credited
Buy bitcoins
Withdraw

MtGox are a reputable exchange and are quick to process GBP deposits (At least for me anyway).

Bank transfer to MtGox costs a lot. If you want to buy only a little it's expensive.

It costs me £16, no matter if I transfer $1 or $100,000 and this it not a MtGox fee, MtGox Processing GBP has no fee, this is purely a bank fee for sending the money to a foreign bank.

Well, seems to me that Hugh is much closer to the $1 than the $100k. ;)

£16 is fine for 100k but as you say Murch - I was thinking £50 or £100.

Don't forget the banks usually round (up) the conversion rates.


text:
Transaction generator with payment fee optimization for large number of small coins
I have a large amount of money in a lot of small coins in my wallet (most of them like 0.0002 BTC).
But whatever I do, I loose about 15% due to transaction fees, because transactions are too large.
Is there any tool for optimization of transactions, which could combine those coins into transactions with minimal or zero fee?

I made the transaction and wasted 15% of bitcoins. There remained a few coins with value of 0.00005 BTC, thus I attempted the uno-wallet's access by private-key and created a transaction with zero fee. It obviously was pending a week in the queue and after that it disapeared. I'll try that once again. From now on, for dust transaction I'm using Inputs.io, which is able to consume single satoshis and add them to my account:)

If the coins are in the same wallet then you should be able to send your "large amount of money" in one transaction.
If your coins are spread across multiple wallets in the same client then you would need to take the 15% loss. Or not pay a transaction fee and hope your coins get validated by a very friendly miner. (I would advise the former.)
In the event that your coins are spread across multiple wallets, you should bite the bullet and send them all to a single wallet so you don't continue losing money in the future.
It also might be a good idea to have slightly larger transactions, so you don't pay as many fees.

I created a transaction with fee a bit lower than the advised value and the transaction has been accepted. But is pending with 0 confirmations and it is not visible in blockchain. Where is such a transaction? Is it only on my local system? Can I get rid of that by droping my wallet or my local blockchain copy?

That's because your transaction has been 'sent' to the network by your client, but has not been added to any blocks. This is because your transaction fee is lower than normal, and miners don't want to add your transaction for free. Which is why I suggested cutting your losses and putting your coins in one address. Now you need to hope there's a miner out there willing to add your transaction to their block, otherwise your coins will be in limbo.

I'm a little confused by your terminology.  I think most people consider a "wallet" to be a collection of private keys for several addresses belonging to the same person.  In this case, the asker has many coins in different addresses within the same wallet.  Since each address needs to be mentioned in any transaction to spend them, the fact that they are all in the same wallet doesn't help with the transaction size.

@Nate I believe it's the OP who is confused. He's saying he has "a large amount of money in a lot of small coins." To me, that means he has a lot of wallets, in one client. To me he seems to be mixing up a client, and a wallet.

So I'm telling him to put them all into one address, so that he can place larger transactions, and, subsequently, lower fee percentages. Though I could be misunderstanding him.

Yes of cause, is clear to me that combining the money to a single coin and paying the correct fee is the only solution. But I just wanted to try to create a transaction with low fee. And now I'm asking, where is the transaction. I thought, that it's ignored and there is some retry mechanism in the client, which will attempt to resubmit that. But if it is only on my local system, I'm able to import the private key somewhere else and create tran with correct fee and this tran would be processed normally. And the bad tran will be rejected at the time of the next attempt. Is it correct?

@VX Unfortunately no. Once you send coins to a different address, there is no going back. Even if it's never broadcast to the network, or even if it was broadcast but you don't have a copy of the blockchain. (That's why offline wallets work.) That is why I recommended using the recommended fee. Since you didn't, your transaction may take a long time to get added to a block. But that's okay! At least you learned with a small amount, and not all of your coins!

You can track your transaction with a block chain browser, like BBE. Also make sure you pay the appropriate fees, and don't send transactions that are stupidly small (like 0.000002 BTC) so as to minimize your money lost to fees.

My question is who knows about the transaction? If it doesn't seem to be visible form the network. Other submitted transactions do appear in blockchain as unconfirmed transaction but this one is "not found" in the block explorer. How should I understand that?

Under your client go to Tools > Reset blockchain and transactions. You may also find this and this useful.

No I don't find those links useful. It is not my case.
I have imported the private keys to multibit and the pending transaction is not there. This way I think, I may create a new transaction using those coins, which I have attempted to send in the other client.

Lets assume you want to consolidate a lot of small unspent Inputs that are signed for use by addresses located on a few clients.
For every client, create a raw transaction with the unspent Inputs you want to spend (send to another address). Somehow join all the raw transactions, and start signing with the first client. Every client will have to sign before the finished transaction is broadcasted to the network.

I'm not exactly sure how to accomplish this, but all the bits of the puzzle exists:
To try this were going to use brainwallet.org with "correct horse battery staple". Then were going to http://brainwallet.org/#tx with that private key to create a raw transaction.
The private key is known and used by a lot of users, so there is "dust" we need to remove with "Edit Inputs". I saved the first and the last unspent outputs, to make this example shorter.
Think of these two unspent outputs belonging to different addresses. Then you need to sign with both to make it an valid transaction.
Take a look at Gavins example for signing a 2-of-3 transaction, notice how the hex is getting longer for every signing and returns "complete: true" when the transaction is valid for broadcast.
The last part is figuring out what fee is required, look at the JSON Transaction and notice "size":xxxx. Now use what you learn here to calculate an appropriate fee. (You need to include the fee before signing)

Import all your private keys with dust to Electrum and use them to pay the fee in your normal tansactions prioritizing them when making payments.


text:
Is it possible to spam the bitcoin network with 'dust'?
Someone could buy or mine bitcoins, and send them in small transactions all day to spam the blockchain.
Is this possible? And could this mean the end of the trust people have in bitcoin?
edit:
And what if someone makes bigger than 0.01 BTC transactions from one of his address to another all day. Making thousands of meaningless transactions, those totally spamming the blockchain. That wouldn't even cost much I believe. Is this possible?

Such transactions will be subject to fees.  You can read about the fee schedule here.  The fees apply if the transactions send a small amount of coins, or send the same coins over and over (giving the transactions a low priority score).
The fee is set at BTC 0.0001 per 1000 bytes.  Thus someone who wants to spam the block chain with 10 MB will have to pay at least BTC 1 in fees.  That's about US$500 at today's prices, and it causes the block chain to increase in size by about 0.1%, which nobody will probably even notice.  If you're going to spend $500 on mischief, you'll get a lot more bang for the buck by spending it on eggs and toilet paper!

So basically the network knows if I'm sending that 0.1 BTC between my 2 addresses all day, and deprioritizes it?

@Rails: Right.  Specifically, it looks for the age of the transaction outputs that are being spent.  If you are transferring coins that were previously transfered a short time before, the priority goes down, and you have to pay a fee to get the transaction recorded.

who gets the fee?

@SuperUberDuper: It goes to the miner who includes that transaction in a block.  http://bitcoin.stackexchange.com/questions/9895/who-gets-bitcoin-transaction-fees/9897#9897

You can create unlimited addresses and then send amounts of bitcoins which are over the fee-less minimum transaction limit to your own addresses.  That means you can technically spam the blockchain for the price of the electricity.
A transaction may be safely sent without fees if these conditions are met:

It is smaller than 1,000 bytes.
All outputs are 0.01 BTC or larger.
Its priority is large enough (see the Technical Info section below)

https://en.bitcoin.it/wiki/Transaction_fees
Anyone know how the bitcoin core could stop you from doing that without blocking your IP from the network??  Even in that case, all you need to do is spoof your IP address over and over again>>>

It's possible, but Bitcoin was designed to have humans filtering transactions for just this reason. Miners have the responsibility to keep the blockchain free of spam, and nodes can help filter it at the network/relay level. Often this is done by only relaying/mining transactions that have certain properties (ie, obviously aren't likely to be spam because they move a high volume of old coins) or transaction fees (so that spamming is expensive). Some spammers exploit human weakness and trick gamblers into paying fees for them, so some miners employ more advanced spam filters to try to identify these as well.

poetic to read this in 2023

There was similar thread of someone sending the smallest amount of bitcoin (probably for spamming puposes) here. However I put on my blog a bitcoin address and so far have recieved any smallest amount. Bitcoin price is pretty high so sending smallest ammout (0.00000001) wouldn't be cost effective spamming.

And what if someone makes bigger than 0.01 BTC transactions from one of his address to another all day. Making thousands of meaningless transactions, those totally spamming the blockchain. That wouldn't even cost much I believe. Is this possible?

Every transaction has to be confirmed and fees are required, miners rely on them. This has been discussed on bitcointalk and very nice explanation is here. Also you can check bitcoinfees.com for informations related too a transaction fee.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
What qualifies as proof of residency for AML in the USA?
I am in a unique situation of not owning or renting property and no need for utilities.  I've tried to contact several exchanges to find out what are all the acceptable forms of proof of residency, but none of them respond.  I don't want to send money until I am sure I can meet the AML requirements, but I can't figure out if I can meet them.  And I don't want to deal with exchanges that are not AML compliant.
Is there a definitive list of documentation?
EDIT:  It's been almost two weeks with no response from 3 different exchanges.  Is there really no list of acceptable standards?  Is it save to send money and just find out if they accept what I can provide?

You could just try sending a small amount of funds. If it works then it works. The try with the full amount (keeping below the exchanges daily limits) As a general rule when you are done I would suggest you move your funds/coins off the platform quickly. This is in-case they are hacked etc (As they are not going to be gov guaranteed like a bank, Caveat emptor)

Problem is I've read complaints from people who have done as you suggested only to have their full funds held up for weeks after the small transfer worked fine.  I assume they eventually got it back or processed.  But it seems odd there's no list of requirements.

From a gox employee:
What does the process involve?
First, we ask you to provide one piece of government issued photographic identification, which is usually either:
A driver's license,
A passport, or;
A military identification card (surprisingly, we have a large number of customers in the armed forces of various countries.)

We then ask you provide some form of proof of residence document, which is an official document issued within the last three months bearing both your name and full street address. For obvious reasons, we cannot accept addresses with PO Boxes. Usually, we receive one of the following:
A utility bill,
An internet bill,
A cell phone or mobile phone bill,
A tax return,
A residency certificate issued by your local government,
A voting registration form, or;
A medical insurance bill

Whilst many of our users submit bank statements as their proof of residence, we unfortunately cannot accept bank statements from our customers. This is because it is relatively easy for fraudsters to open an account at a less reputable banking service which does not check the accuracy of a person's stated address. It is then possible to use this bank's statement as a seed to open accounts at increasingly trustworthy establishments without ever having provided proof of residence in the first place.

There is not. You will not find a definitive list of allowable documents, endorsed by a government, regulatory body, trade group etc. You may find lists of generally accepted documents, however there is no guarantee that their acceptance is either uniform or universal.
Documents typically considered acceptable for the purposes of establishing residency at a given dress i.e. rental agreements, mortgage documentation and utility bills (such as gas, electric, water) are generally utilized (and accepted) by the financial institution as they tie the individual directly to the address thereby satisfying elements of AML/CFT, specifically the Know Your Customer and Customer Identification Programs.
Your only option is to await a response from the specific institution (in this case exchange) and inquire as to what documents they will accept in lieu of the aforementioned, if you are unable to provide them.

I've waited over a week.  My concern is they won't respond.  And if I test the system with a small amount of money it might work, but then larger amounts could get held up.  I worry about getting the funds back in this case.

I don't think AML is unique to the US. Fundamentally, the answer is probably heavily correlated the ability of a government to enforce its jurisdictional laws upon individuals whether citizens or not.  "US Persons" are subject to US laws even though they may not be citizens. A US Person has an active green cards. Binding a form of identity (e.g., driver's license, passport) to a location of where you live will be imperative. Otherwise, laws can't be enforced unless you can be found.

My question was meant to imply required documents available to an average US resident.


text:
Does my Bitcoin-Qt wallet backup file have "everything" I need (private key)?
Does my Bitcoin-Qt wallet backup file have "everything" I need (private key)?
I mean, is that the file I would copy and store offsite in case my house burns down? Does it have my private key encoded in there?

It is not clear to me which file you deem to be the "bitcoin-qt wallet backup file".

Potential duplicate of How should you backup your wallet?

You only need to copy the wallet.dat to backup your private-keys. Do this while Bitcoin-Qt is not running. All other information will be deduced from the blockchain once you re-import the wallet.dat except any custom labels you have given to addresses.
Of course, if you encrypted the wallet.dat you will also have to remember the passphrase.

So does the "Backup wallet..." menu item simply copy wallet.dat?

Oh, I was unaware that such a menu item had been introduced to Bitcoin-Qt. Now, from what I read it should be safe to use even while Bitcoin-Qt is running. (The manual copying of the wallet.dat should only be performed when Bitcoin-Qt is not running.) I would assume that it also just copies the wallet.dat, but I didn't find anything that specifically explained which files it stores. Will check it out later, going to be now though.

It's a litecoin-qt wallet - I just assumed it was the same as the bitcoin one.

The bitcoin-qt wallet also has "Backup Wallet..." menu option.


text:
Bitcoin wallet shows empty after I installed Windows on SSD
My PC stopped working a while ago (BSoD on every restart). I bought an SSD and installed Windows 7 64-bit on it (same as I had on my HDD). I then attached the HDD back into my PC and intended to back up everything important before I formatted it. All my old files are still on the HDD, including Bitcoin-Qt and my wallet.dat. Which is why my coins should also be there, right?
I now opened my wallet, but I noticed it shows my balance is 0.00 BTC. It hasn't yet synchronized fully with the web (about 23,000 blocks left as I'm writing this), and shows it's not up to date. It also shows none of my transactions or anything.
Previously (before buying the SSD) the wallet still showed my BTCs despite it not being fully synchronized.
I have tried to run Bitcoin-Qt with the -rescan command, but this didn't help.
Is there anything I can do to see if my coins still are there and to get them back? I'm afraid that if I let it synchronize fully then all this becomes somehow permanent..

This may sound stupid but you did in fact move the wallet.dat file back into the Bitcoin data directory right?

Depending on how recently you purchased/mined your bitcoins, the fact that your client hasn't synced might be why you don't see any balance being shown.
The reason for this is that your wallet doesn't actually contain any physical data representing coins, it simply contains keys that allow you to spend the values associated with a specific address. The way that the bitcoin network determines the number of coins associated with an address is by traversing the entire blockchain and summing all of the transactions including that address. When the bitcoin qt client is syncing, it is downloading this blockchain. Therefore, if all of your transactions happened in the blocks that you have not downloaded yet, it will look like your wallet contains no coins.
This means that the solution to your problem may be to just wait until the bitcoin client has fully synced. If/when your client downloads the blocks with your transactions in them, your balance will be updated. If your client syncs and you do not see your balance change, that means that the bitcoin client is not reading the correct wallet. Make sure that you have copied the wallet.dat file from your old hard drive to the correct place on your new one. NOTE: Make sure that the bitcoin client is CLOSED when you copy the wallet.dat file.
If your client has fully synced and you are sure that the correct wallet.dat file is loaded, and you still do not see your balance updated then you are probably out of luck. If you have lost the cryptographic keys stored in your wallet.dat file, the damage has already been permanently done.


text:
btc-e current btc withdrawal fee
Hello can anyone answer me whats the current btc-e withdrawal fee?
The only source of information i can find is this which says it's set to 0.01 btc. Is it still valid?

there are multiple methods of withdrawal transactions that very based upon the method chosen

You can see current fees only after registration on the btc-e.
Follow to "Finances", click "Withdraw" in the Bitcoin line.
Or login and follow the link:
https://btc-e.com/profile#funds/withdraw_coin/1

Min amount for withdrawal - 0.002 BTC.
Be patient, transfer of funds will be before the first confirmation.
Fee for withdrawal is 0.001 BTC.
Daily limit on withdrawal - 100 BTC.

Ways and fees to withdraw and to deposit are often subject to change on btc-e, thought for a long while (longer than 2 years) the Bitcoin withdraw fee is stay the same: 0.001 BTC.
When btc-e change rates, add new withdraw or deposit method - they usually tweet about it.
https://twitter.com/btcecom
Sometimes they also can add a piece of "news" when a fee is changed: https://btc-e.com/news

There are multiple ways to withdraw from BTC-E however since you asked specifically in terms of BTC the current withdraw fee (Dec 13, 2013) is stated on the website:
* Fee for withdrawal is 0.001 BTC.

Where do you see this stated on the site? It doesn't appear under FAQ nor is it in their withdrawal section of the site.


text:
Write an android application
What is the best way for me to go about writing a new Bitcoin wallet application? Is piggybacking off API's like blockchain.info or coinbase a good tactic? Would the application then be OK to distribute (are said services open source?). Are there alternatives? Can I run my own Bitcoin server and write my own API to go with it instead? What would the steps be involved in that? Would your average punter trust a (legitimate!) wallet that I create or would they feel safer using an app that is built upon a renowned service?

A hosted wallet, which will involve a wallet running on a server that has all the wallets is a bad idea in general. People will not feel safe as they have to trust a third party with their coins and you'd have to implement a whole backend system.
Piggying off Coinbase or a Blockchain is a bad idea, the services themselves may send you a Cease and Desist as you may send a lot of requests and end up swamping their servers, also you'd be copying the functionality of their apps.
You can write a full node, but a mobile phone may not have enough ram and storage to efficiently and quickly do that.
The only nice, viable and realistic approach is creating an SPV client like Electrum for the mobile platform. SPV clients aren't full nodes, they put a certain amount of trust on third parties, but the amount of trust is incredibly small and always double checked. Their main method of work is just requesting data from servers, etc. You can use the Electrum protocol instead of rolling your own as well, you won't need to host servers as well doing that as the community runs Electrum nodes themselves.

"You can write a full node, but a mobile phone may not have enough ram and storage to efficiently and quickly do that." Can I not write a full node on my computer and query that with mobile device? It has been mentioned that the JSON API is an option?

@JoeAustin That will be the same as the 1st or 4th option depending on what do you want to delegate to your main computer. The problem is that having the full blockchain is not an option for mobile so you need some way to trust someone and delegate the process of getting just the transactions you need while being sure that the they are real.

My phone is more powerful than my PC...

You can fork Bitcoin Wallet, an SPV implementation of the Bitcoin protocol:
https://github.com/schildbach/bitcoin-wallet
It's GPL licensed.

Take a look at this:
www.boetchain.com or https://play.google.com/store/apps/details?id=com.boetchain.bitcoinnode
It still very early, so for now, only maintaining connections with peers are available - but it is a start.
Disclaimer: I am a dev on the project


text:
How do I prevent Bitcoin-qt from having to keep reindexing the blockchain?
Is it likely that anti-malware or anti-virus software is causing this issue? (I have told such programs to exclude the Bitcoin folders from scans)

when does it reindexing? it has to finish it onces and wont do it again after.

Like the previous comment: has it finished once? If it has been up-to-date once, the re-indexing shouldn't occur anymore. When you quit Bitcoin-Qt before that point, it has to re-index again


text:
A question about CTransaction::UpdateCoins() in 0.8.6
The logic of this function is quite simple:
1, mark inputs spent
   Call coins.Spend()
2, add new outputs to database.
   Call inputs.SetCoins()
My question is in step1, it invalidate the old output because it has been spent.
But in function coins.Spend(), I only found it kick out the spent output, I didn't find  where the function update the database. If the old output is kicked, the database should also be updated, but coins.Spend() is only update the memory data structure.

Looks for pcoinsTip->Flush(), which batch updates the underlying database CCoinsView.
It is not called for every update as that would require many writes. The way it is implemented now means many outputs can be added and marked spent entirely without needing to hit disk. The result is a disk database that is slightly out of data with the memory version, which means more work to redo when a node crashes, but this case is rare, and having faster block relay is more important.


text:
How do I set up my machine to process transactions and earn the transaction fees?
I am unable to earn money from solving blocks, but I think I could make money from transaction fees. The issue is that pools hide the transaction fees from the miners. The miners earn the solved blocks. How would I go about processing transactions on my own?
This will satisfy two goals:

earn transaction fees
any transactions I perform, I can process myself

The only way to collect money from transaction fees is to solve blocks; they are one and the same thing. The reward for being the first to successfully mine a block is:

the coinbase reward (currently 25 BTC), and
any transaction fees for the transactions included in the block

There is no way to separate these two.

I believe that is incorrect because that would imply that we cannot process transactions after running out of coins. As a result, they must be separate components. Unless, it's the value of each block that is being halved, not the computational complexity of each block being doubled (my assumption is the later because we increase the number of leading zeros on the proof of work).

No, that doesn't imply such a thing at all. After the coinbase reward reaches zero in 2140 or whatever, the only reward miners will receive is the transaction fee component. The complexity of the mining transaction (the so-called "difficulty") is adjusted up OR down every two weeks to match the network performance, independent of the predetermined coinbase reward reduction schedule.

It looks like my assumption, required for my reasoning to follow does not hold. The reason we run of out coins is because the value of mining a block is reduced over time: ( https://en.bitcoin.it/wiki/Controlled_supply ) not because it becomes more computationally difficult. Thanks for your help.

The short answer is: You still have to mine a block, the transaction fee is added to the block reward.
The detailed answer: The idea of transaction fees is to supply miners with enough BTCs so the can keep on mining blocks. Because we keep all transactions on the block chain, it's important for the BTC ecosystem to have a big miner community. Eventually the prize for solving a block will drop, but the number of transactions will increase in such a way, it'll add sufficient number of BTCs to the miners.
After a point, BTC price will hopefully high enough to give miners a incentive to continue mining.


text:
Is there a way to change the wallet.dat location without changing the entire data directory?
I know that Bitcoin supports the -datadir command line option which specifies that the wallet.dat and blockchain should be stored in a custom location rather than %appdata%\roaming\bitcoin but is there a way to specify a wallet location without also changing the blockchain location? I have a highly secured spot I'd like to stash my wallet.dat in (permanently) but I don't want to stash ~2GB of blockchain data alongside it.

Not an exact duplicate, but asking about how to change the default storage location has been posted many, many times. The future canonical question is probably Bitcoin-Qt setup: Change block-chain file location, settings? documentation?.

A symlink will do it on Linux.
On Windows there's a symbolic link method as well:

http://en.wikipedia.org/wiki/Symbolic_link#Windows_7_.26_Vista_symbolic_link

A -walletdir= feature has been requested before:

http://bitcointalk.org/?topic=2730.0
https://github.com/bitcoin/bitcoin/issues/68

+1 That's what I do. But sometimes the symlink gets clobbered (fortunately, just the link, not the wallet): https://github.com/bitcoin/bitcoin/issues/660

That's fantastic, how did I not know Win7 had symlinks?!

The next Bitcoin Core release will have -walletdir, which'll basicly allow you to do it without requiring tricks.
https://github.com/bitcoin/bitcoin/commit/0530ba0eae147563921b162ed05347234d8b53c0
https://github.com/bitcoin/bitcoin/pull/11466


text:
How can I buy bitcoins using Western Union (October 2012)?
I would like to use Western Union to buy some Bitcoins. I have carefully read Bitcoin's wiki page about buying Bitcoins now I'm after users' input about which service they would recommend.
There's a lot of services and I am just after the quickest and safest (like everyone I guess). Could, you guys, recommend a service you find to be the best please?

Western Union is a hassle and is expensive.   Bitcoins Direct was accepting WU payments until just a couple days ago.  In the U.S., about the last exchange to accept WU (USD) for bitcoins is:

http://www.QuickBitcoins.net

In the EU there is an exchange that accepts WU (EUR):

http://bitcoinsinberlin.com

There are also some others.  For instance:

http://www.ecurrencyzone.net/buy.php
http://www.coinmama.com

As far as other options, the factors relevant to providing the right advice include:

Where are you located (country)?
How much are you looking to buy?
What payment methods do you have available?
How soon do you need access to the proceeds?
Is privacy important?

Quite simply, depositing cash at a bank or 7-11, Walmart, CVS is going to be the fastest and easiest way.
Options:

http://www.BitInstant.com (Deposit at major banks, 7-11, Walmart, CVS, Moneygram, etc.,)
http://www.BitMe.com (Deposit cash at Chase)
http://www.BitFloor.com (Deposit cash at Chase or Wells Fargo)
http://www.bitinnovate.com (Deposit cash at a bank in Australia & New Zealand)
http://www.CAVirtEx.com (Deposit cash at several banks)
http://www.Spendbitcoins.com (Deposit cash at a bank in Australia)
http://BitcoinNordic.com (Purchase CashU or UKash in dozens of countries)
http://www.BTC-E.com (Deposit cash (USD) at bank locations in Russia)
http://www.BitNZ.om (Deposit cash (NZD) at back locations in New Zealand)
http://www.BitInstant.com (In Brazil using Boleto or Banco Recomendito, or in Russia, using Qiwi or Cyberplat.)

Also, Bitcoins Direct will accept cash, but they have a $500 minimum order size:

http://bitcointalk.org/index.php?topic=87094.0 (Deposit cash at Bank of America, Wells Fargo or PNC, minimum $500)

Or you might find a local trade (paying cash):

http://www.localbitcoins.com

The fees aren't trivial but you can use a credit card to purchase by using VirWoX where you can buy SLL using your credit card, then trade SLL for BTC:

http://www.VirWoX.com

Or if you are considering a bank transfer, there all kinds of options are available:

http://en.bitcoin.it/wiki/Buying_bitcoins

There is also #bitcoin-otc where you can connect with sellers via IRC:

http://bitcoin-otc.com/

Buying  bitcoin with western union westernuniontobitcoins.com  is very easy, being one of the few that allows you to transfer money online directly to  bank account or to a person authorized to raise money from an office W.U

http://westernuniontobitcoins.com

Thank you for extensive reply. This really does help ! And in your reply I have found what I couldn't even imagine existing where I live (Paris, France): cash for BTC exchangers (your link http://localbitcoins.com) which is absolutely perfect since I have found a guy living really close to mine. So I have contacted him and I'll just go to his place with my laptop, exchange cash for BTC at a very nice rate (more or less Mtgox's) which is absolutely perfect. It's instant, anonymous, quick and free of fees.
Thank you so much !

You probably will have the best luck on Bitcoin OTC. It's a service allowing you to trade person-to-person, so you can use any means that someone else will find acceptable.

Great, I like the idea. Thank you for the heads up ! I guess one could easily get scammed though.

@user2021 That's why there is otc rating. Pick your risk wisely based on it.


text:
What is the cheapest Cash-to-Bitcoin Service?
There seems to be a few services to purchase bitcoins from out there, as in bitinstant, MtGox, bitcoin.de, etc.
I would like to know if someone has looked around to find the one with the cheapest transaction fees for buying/selling bitcoins.

The factors relevant to providing the right advice include:
Where are you located (country)? How much are you looking to buy? What payment methods do you have available? How soon do you need access to the proceeds? Is privacy important?

I am located in europe, payment options include CC, paypal, SEPA transfer and cash, while paypal itself already charges fees for transactions. Privacy is preferred, but trust is more important. The amounts of selling/buying will be low for now, until I have trust in the system.

This question is currently too localised, and will likely become out of date. Have raised the issue for discussion here (http://meta.bitcoin.stackexchange.com/questions/311/cheapest-question-will-get-out-of-date), but perhaps the question should be closed.

That would probably be either Bitcoin OTC or Local Bitcoins, as you are trading directly between people. This way you can barter for better rates and you don't have to pay a fee.

In the U.S., the least expensive method is a Dwolla transfer to an exchange that accepts Dwolla (Mt. Gox, and Camp BX).  Dwolla charges $0.25 per transaction when the amount transferred is over $10.
Quite simply, depositing cash at a bank or 7-11, Walmart, CVS is going to be the fastest and easiest way.
One method that was the least expensive, depositing cash at an exchange's bank, is currently unavailable as the exchange that offered that (BitFloor) has suspended that method, temporarily apparently.
BitMe offers this but they don't have much liquidity yet (on the sell side) so that might not work.
If you are looking to deposit $500 or more, then Bitcoins Direct will accept that cash:

http://bitcointalk.org/index.php?topic=87094.0 (Deposit cash at Bank of America, Wells Fargo or PNC, minimum $500)

All other cash deposit options:

http://www.BitInstant.com (Deposit at major banks, 7-11, Walmart, CVS, Moneygram, etc.,)
http://www.BitMe.com (Deposit cash at Chase)
http://www.BitFloor.com (Deposit cash at Chase or Wells Fargo)
http://www.bitinnovate.com (Deposit cash at a bank in Australia & New Zealand)
http://www.CAVirtEx.com (Deposit cash at several banks)
http://www.Spendbitcoins.com (Deposit cash at a bank in Australia)
http://BitcoinNordic.com (Purchase CashU or UKash in dozens of countries)
http://www.BTC-E.com (Deposit cash (USD) at bank locations in Russia)
http://www.BitNZ.om (Deposit cash (NZD) at back locations in New Zealand)
http://www.BitInstant.com (In Brazil using Boleto or Banco Recomendito, or in Russia, using Qiwi or Cyberplat.)
http://www.bitXoin.com (Deposit cash over the teller at Major Australian Bank Branches)

Alternatives:
If you are in the U.S., there is one vendor that apparently is offering to sell via credit card.

https://www.quickbitcoins.net

The fees aren't trivial but you can use a credit card to purchase by using VirWoX where you can buy SLL using your credit card, then trade SLL for BTC:

http://www.VirWoX.com

There possibly are other options that will work for you as well:

http://en.bitcoin.it/wiki/Buying_bitcoins

Last of all there is #bitcoin-otc where you can connect with sellers via IRC:

http://bitcoin-otc.com/

For SEPA transfers, Bitstamp may be what you want. I've been using it for months now. There is no deposit fee (just what you pay to your bank for the SEPA transfer), and you pay up to 0.5 % fee when you buy BTC (this was actually free last week but you missed it). There is also some currency conversion expense (your EUR will be converted to USD), but they use ECB's currency rates which are quite good, and don't take any fees themselves for conversion. Also the exchange is quite liquid (third largest USD market) so the spread won't cost you much either.
If you're just buying BTC, this is it. If you plan to withdraw EUR from the exchange, you'll also pay 0.90 EUR per withdrawal.
Also all SEPA transfers are processed in 24 hours, sometimes the same day.


text:
How to find partners for a Bitcoin business?
Are there any resources available to find people who are interested in starting a Bitcoin-related business?
To answer comments:
I am looking for both partners who want to start a business and investors. Something related to bitcoin that is delivered via internet. Perhaps a stock exchange denominated in Bitcoin, algorithmic trading in Bitcoin, etc. I am open to many different ideas.

Generally a startup business will be a founder or pair of co-founders, until they have something to sell.   Or are you asking about "financial" partners / (investors)?

What sort of business are you starting and who do you need? I might be interested... ;)

@ThePiachu and - B Seven, I am open to new ventures as well.  I have a Butterfly Labs Mini Rig on order.  With custom mining software many things are possible.  Find me at my name at gmail.

I think posting your ambitions here would return quite some feedback/interest:
https://bitcointalk.org/index.php?board=12.0

And this one: http://bitcointalk.org/index.php?topic=20292.0


text:
Gui shutdown: message in the terminal
I closed down bitcoin from the official gui client with File > Exit and the following message appeared in bash:
************************
UNKNOWN EXCEPTION
bitcoin in CMyApp::OnUnhandledException()

I've seen this before, and on restarting bitcoin, I encounter no problems, and transactions work just fine. Does anybody know what is causing this error message to show?
I'm running debian squeeze just FYI.

I see several reports of this bug but no solution or analysis. Unfortunately, the error message contains almost no useful information.

This is a bug report and as such very localized in time. Not suitable for this site IMO.

Here's its filing on github.  Seems to be an unresolved issue with the client.


text:
Which blocks get to be checkpoints?
Which blocks get to be checkpoints, and why is one block chosen to be a checkpoint, rather than another block? And where can I find a list of checkpoint blocks?

At least in Bitcoin Core, none. Checkpoints are legacy and will likely be removed at some point.
Checkpoints were originally introduced as a way to enable skipping of signatures in the historical chain, without being vulnerable to accepting an alternate history. That role has now been overtaken by the assumevalid concept (a block hash that is known to be good, but doesn't prevent accepting another chain).
Checkpoints have also been used as a heuristic to know what block headers are acceptable before validating an entire block. That role was removed with headers-first synchronization in 0.10. We now only download a block after we already know its proof of work and difficulty are acceptable.
They have also been used as a measure for validation progress (so Bitcoin-Qt can show a progress bar during validation). That role has been replaced with just statistics data that doesn't affect validation.
The only thing checkpoints still serve for is preventing a low-difficulty headers attack, where your node gets spammed by a large number of long, low difficulty chain branches, making it go out of memory. Due to the existing checkpoints (up to height 295000), this is a very costly attack already.

You can find the list in bitcoin source code.
These are the current checkpoints (from git revision c091b99):
    checkpointData = (CCheckpointData) {
        {
            { 11111, uint256S("0x0000000069e244f73d78e8fd29ba2fd2ed618bd6fa2ee92559f542fdb26e7c1d")},
            { 33333, uint256S("0x000000002dd5588a74784eaa7ab0507a18ad16a236e7b1ce69f00d7ddfb5d0a6")},
            { 74000, uint256S("0x0000000000573993a3c9e41ce34471c079dcf5f52a0e824a81e7f953b8661a20")},
            {105000, uint256S("0x00000000000291ce28027faea320c8d2b054b2e0fe44a773f3eefb151d6bdc97")},
            {134444, uint256S("0x00000000000005b12ffd4cd315cd34ffd4a594f430ac814c91184a0d42d2b0fe")},
            {168000, uint256S("0x000000000000099e61ea72015e79632f216fe6cb33d7899acb35b75c8303b763")},
            {193000, uint256S("0x000000000000059f452a5f7340de6682a977387c17010ff6e6c3bd83ca8b1317")},
            {210000, uint256S("0x000000000000048b95347e83192f69cf0366076336c639f9b7228e9ba171342e")},
            {216116, uint256S("0x00000000000001b4f4b433e81ee46494af945cf96014816a4e2370f11b23df4e")},
            {225430, uint256S("0x00000000000001c108384350f74090433e7fcf79a606b8e797f065b130575932")},
            {250000, uint256S("0x000000000000003887df1f29024b06fc2200b55f8af8f35453d7be294df2d214")},
            {279000, uint256S("0x0000000000000001ae8c72a0b0c301f67e3afca10e819efa9041e458e9bd7e40")},
            {295000, uint256S("0x00000000000000004d9b4ef50f0f9d686fd69db2e03af35a100370c64632a983")},
        }
    };

It doesn't really matter how they are chosen, but notice the following comments found in the source:
/**
 * What makes a good checkpoint block?
 * + Is surrounded by blocks with reasonable timestamps
 *   (no blocks before with a timestamp after, none after with
 *    timestamp before)
 * + Contains no strange transactions
 */

Anyway, as long as they are inserted at regular intervals everything is fine. This answer gives a hint at what is their purpose.


text:
My transaction not successfully sent
1QEu9KydPdKxAQFcJKxzwFJYcrsSZdT6Zr
Hello support I made this Transaction since 10th November 2017 and since then the transaction has remained unconfirmed. I paid the required transfer fee but don't know what's wrong. Please I need you help

Just wait: https://blockchain.info/en/unconfirmed-transactions

Those are new transactions coming in, mine is over 48 hours now


text:
How to get the number of Bitcoin transactions every 30mins using API in python?
I'd like to get number of Bitcoin transactions every 30 minutes using API in python.
Does someone know sample code how to mount in Github or any website?

This question is a little vague, and should probably be changed if you want any answers.  You should probably ask this in two separate questions.  First, how to count transactions per half hour on the Bitcoin network.  After that is answered, post another question asking about a python library that can help with whatever the answer to the first question was.  That will likely yield better answers than the current question.

You can use the blockchain.info api (https://blockchain.info/api) and then track in your database the different number of transactions based on any time you would like.


text:
bitcoind error "mempool min fee not met" preventing me from sending btc on blockchain
When I want to send btc in block chain this message is appearing:

BitcoindException(super=com.neemre.btcdcli4j.core.BitcoindException:
  Error #-26: 66: mempool min fee not met, code=-26).

Who knows how to resolve this? Can anybody help me please?

TLDR it probably means tx traffic is high and you need to set a higher feerate on your transaction.
"mempool min fee not met" isn't the minimum relay feerate setting (-minrelaytxfee); that error is "min relay fee not met".
When you get "mempool min fee not met" error, that refers to the node's dynamic mempool minimum feerate. It means the node's mempool reached capacity and started evicting the lowest feerate transactions, and temporarily raised the minimum feerate beyond the minimum relay feerate (to avoid accepting stuff that's going to be evicted immediately afterward).

related: What if the mempool exceeds 300 MB?

Some servers set custom min Mempool fee, so the server that blockchain chose has set that option.
In blockchain.info you can't choose custom bitcoin server, So you should get your recovery phrase and import it in electrum since they support this feature. Or you can just wait until that server gets change.

It seems to be a known issue on Electrum. Try a different server:   https://github.com/spesmilo/electrum/issues/3555#issuecomment-352621941


text:
Mistakenly sent BCH to BTC bitfinex wallet - can I get my BCH back?
I just made the huge mistake to sent BCH from Exodus to my BTC wallet in bitfinex. Can I by any chance get my BCH back?

BCC? BCH and BCC mostly means Bitcoin Cash. Do you mean Bitconnect "BCC"?

Sorry.. That was stupid.. I have sent Bitcoin Cash from exodus to my Bitcoin wallet in Bitfinex.. @MCCCS

Possible duplicate of Bitcoin Cash accidentally sent to Bitcoin address. Can I get them back?

@PieterWuille Probably. But I do not know how to find my private key in Bitfinex. And furthermore, if I find my private key in Bitfinex I will not know how to import it in Exodus? (Yes I am pretty new in this game)

They will be recoverable, but only by the exchange the money was sent to.

Can you be more specific? I am pretty new in this crypto-world, so all help would be much appreciated! @eponymous

Bitfinex will need to assist you to recover your mis-directed transaction.

bitfinex expects that you send btc to address xy, because xy is a wallet of bitfinex. so bitfinex has the privatekey of xy. but you sent some bch to xy on the bch-blockchain. the private key of xy is the same on the bch- and on the  btc-blockchain. so bitfinex can (if bitfinex is accommodating) send your bch back to you. (or bitfinex could deposit this bch-value to your bitfinex-bch-wallet.)
they can definitively, but they must not. this depends probably on the effort of a bitfinex-employee

@KarenMarieSteffensen, please don't use crypto to mean cryptocurrencies. crypto == cryptography, not cryptocurrencies

Its nearly impossible to recover. The BTC address you sent the BCH to is (very much possible) not even owned by anyone.

actually, you can use the private key from the BTC wallet to create a BCH wallet.  Of course, this only works if you have the private key for the BTC wallet, which the OP clearly does have.

@MaxVernon, it is my wallet but I do not know how to find my private key in Bitfinex? I have found it in Exodus, but that does not help me out does it?

No, you'd need the key for the bitfinex account.  Contact bitfinex to see if they can help you.


text:
Recover old ufasoft coin wallet from a wallet.db file
I found a wallet.db on my computer which was used with the Ufasoft Coin application. Of course I want to see if there is anything left in this wallet so I downloaded the Ufasoft software from some shady download page but I can't find any way to open the old .db file, anyone tips?

For starters, if you don't trust a piece of software, don't give that software access to a wallet file.  That's just asking to be ripped off.
I am unfamiliar with "Ufasoft", but a quick web search makes it appear to be a small software company that at one point in time created a CPU/GPU bitcoin miner and wallet.  If that's the case, then you may need to reach out to that company for support.  The wallet file may not conform to the Bitcoin standard.  In fact, it looks like the wallet supported many coins, so it might be some hybrid multi-coin wallet format.
Best of luck.  When you use non-standard wallets, you'll end up not being able to ask the larger community for support.


text:
Electron Cash wallet password not working!
I downloaded the wallet software from electroncash.org, version 2.9.4. I then transferred some Bitcoins from Coinbase using shapeshift to my new BCH wallet and after a few minutes, saw my tokens alright.
Then 2 days later, when I fired up the software again, my password didn't work!
Can you help me? I got the seed phrase but how do i use it?
When I fire up the software, the only wallet to choose is default_wallet. I also see the password field just below the pull down menu to select my wallet. I also tried entering the seed phrase into the password field.

I guess you transferred BCH to your BCH wallet?  Not bitcoins hopefully.

Possible duplicate of Electron Cash Wallet now suddenly not accepting password?

FOUND A SOLUTION!!!!  Once the software is loaded, you just create a new wallet. You do this by entering a new name in the field. Then it will ask you to create a new wallet. You just enter your seed phrase once prompted and BOOM, your tokens appear YAHOOO!

@Andre: Could you please post this as an answer instead of a comment?

I had same problem, and found a solution. If you a open new wallet by importing your private keys (and import only adresses without keys,) then you will get read-only wallet, so on another PC I opened another wallet, imported private keys only, not adresses, and didn't encrypt it with password, then the wallet started to work properly.

Can you help me? I got the seed phrase but how do i use it? When I fire up the software, the only wallet to choose is default_wallet.

Type in a unique filename instead of default_wallet. Say wallet-restoration-62907. Then click next and choose 'standard wallet' and next again and then 'i already have a seed'. Continue as per on-screen instructions to restore from seed.

Try it with the caps locks on. For me it was that the application wasn't telling me that my caps lock was on. Then, on restart, "Wrong password." Etc.


text:
Where did my money go after I sold bitcoins to BitZIZ into PayPal?
I am new to this and hate it. I had $2340 in US dollars to sell in bitcoins. I needed the cash desperately for rent and car payment and food, so went through BitZIZ to deposit the money into my PayPal account. I received an email that said the transaction was complete and the funds were in PayPal. No they weren't. They are gone. I have nothing in PayPal, so I guess I'm down and out. When I contacted BitZIZ many times, no answer. When I contacted PayPal they said nothing was sent to them so my balance is zero. I am heartbroken...NEVER AGAIN. This money meant the world to me

Unfortunately, this is coming a bit too late to do you any good,but: Don't ever send bitcoin to anyone you don't completely trust.

Looks like there are multiple cases of other customers reporting the site as a scam, so it's likely you'll never get a response from them, unfortunately.
Because most cryptocurrency transactions are irreversible and often somewhat anonymous, it is important to first check the reputation of any entity you're dealing with.

You'll need to contact BitZIZ to get your money.

I tried a dozen times and will not respond, thanks anyway


text:
How can you find how many keys you wasted in bitcoinj?
Supposed you create a new wallet and pre-populate it with 100 keys (so you don't need to back it up after each transaction).
How do you know, given an instance of Wallet, which keys have been "used up"? Or, in other words, if you want to use a new key for every transaction, how do you which key to use, given only the wallet state?
Are you supposed to save this information elsewhere?

Wallets contain a pool of 100 unused keys plus every key ever used. You can never run out of unused keys because the client adds new keys to the unused key pool as you use them.
The reason it maintains a pool of unused keys is so that future transactions that happen after a backup can still be recovered.
You should frequently back your wallet.dat up off-site using non-flash media. You should also backup your wallet.dat after every 50 send transactions (receive transactions do not use up unused keys unless you frequently create new addresses to receive coins with, which would also use the key pool up; in that case, every 50 transactions of any kind).


text:
How does blockchain.info detect double spends?
http://blockchain.info/tx-index/242749/36080ed09eeb0fd66ad5dc8a909a49e364f55ff860c12327c2ff9fbe4a9dde77

Warning! this transaction is a double spend. You should be extremely
  careful when trusting any transactions to/from this sender.

All valid transactions are relayed through the network. A client does not know which transactions will be a part of a block, so it stores and relays both double-spent transactions. If you regularly poll your bitcoind, you can see every transaction before it is put in a block. Then it is just a matter of checking txin data for duplicate inputs.

The bitcoin network does NOT relay unconfirmed transactions that double spend other unconfirmed transactions, so neither blockchain.info not anyone else sees most unconfirmed double-spends.  Nodes do not store two conflicting spends - they store only the first one they see.
This is becoming a bigger challenge for merchants because they need to connect to thousands of nodes in the hope of spotting double-spends.
The Bitcoin XT patch set is an early release of functions that are proposed for Bitcoin Core.  It does relay double spends, and notifies the wallet of double-spend attempts that affect it.


text:
How do Scripts work?
Bitcoin protocol supports scripts.

How do they work?
How are those implemented?
What are their intended usages?
When are they planned to be used?

I asked this as one question, if you think it's more appropriate as separate questions let me know.

Related question providing script references: http://bitcoin.stackexchange.com/q/547/117

Scripts are one of Bitcoin's more clever features. The most obvious way to implement a crypto-currency is to make a transfer be to a public key. To claim the transfer, you sign with the corresponding private key. This is not the way Bitcoin works.
When you send Bitcoins (the out of a transaction), you send them to a script. When you claim Bitcoins (the in) of a transaction) you claim them with a script. To determine if a transaction input correctly claims a transaction output, the two scripts are combined and the result is executed. If the result is true, then the input claims the output. The scripting language is stack-based and roughly similar to Forth.
The transaction input (the script trying to claim the Bitcoins) runs first. It will typically put a public key and a signature onto the stack. Then the output (the script whose Bitcoins are being claimed) runs. It will typically confirm that the public key is the correct one and that the signature signs the transaction with the corresponding private key.
Thus, you get the same effect as if you just specified a public key and signature, but you have the option of specifying more complex scripts. Unfortunately, this kind of simple script is pretty much the only kind of script supported right now. The original developer(s) imagined much more interesting scripts including things like contracts, multi-party signatures, and so on.
M of N signatures are planned. This way, you could list, say 3 public keys such that any 2 of them could claim the Bitcoins.
Unfortunately, some of the scripting components are feared to have security risks, so many of them are disabled currently.

Coolness. I never knew how integrated scripts were to the protocol.


text:
After mining litecoins for about two hours, how long will it take for anything to go into my account?
I've been mining now for about two hours. How long would it take for anything to appear in my account?

possible duplicate of How long to earn fractions of bitcoin

Possible duplicate of In the ASIC-age, is it worth starting mining Bitcoin at home?

This depends on a lot of things including what kind GPU's you are using and if you are pooled mining or mining with the main client. If you are solo mining with a GPU you will most likely not see anything for a very long time or at all. You can use this to determine how much you would make mining with a pool https://www.litecoinpool.org/calc. I don't mine litecoins myself but it seems that https://www.wemineltc.com is a popular pool for people who do.

Most cryptocoins require 120 confirmations (additional blocks added to the chain) before the block reward is granted. I'm not sure about Litecoin, but if that's the case, and if you are solo mining, or if your pool doesn't take any chances, the first reward will be 120 confirmations after the first mined block.
And since blocks are mined about every 2.5 minutes, that's about 5 hours.


text:
Spending bitcoins - what happens to the change left in your address?
How do I manage my wallet and addresses when spending bitcoins?
For example, let's say I have address abcdefgh, and I have 10 Euros there. I read that when I buy something worth say 4 euros in bitcoins, I must then spend the rest on another unused address, zyxcvbnm, as the first address becomes unsafe or the change is lost in mining fees or something. It this true? Are all spends a double spend? For example, once for the item you want and once to your savings address?

Stop thinking in EUR! It's only complicating the question. Also: sending money to two addresses is not a double-spend. https://en.bitcoin.it/wiki/Double-spending

I assume you're using Bitcoin-Qt, i.e. the reference implementation.
Bitcoin-Qt works with accounts, not addresses. The balance of your wallet is the sum of each account balance. The purpose of accounts is to compartmentalize payments in labels such as "Savings", "Salary", "Friends", etc. for your own convenience.
Each account has many Bitcoin addresses associated with it, though you'll only see one at a time (the last one). As soon as you get a payment in the displayed address, its address will change. You can still receive payments at that address, though that is considered bad practice due to anonimity issues.
Now to answer your question: "I read that when I buy something [...] I must then spend the rest to another unused address [...] as the first address becomes unsafe or the change is lost in mining fees or something."
Bitcoin works a bit different than money. A payment is:

References to earlier payments you received (i.e. the sources of money)
A list of pairs of (address + amount) (i.e. destinations)

When you reference an earlier payment you must spend it as a whole. You can't split it, like you wouldn't be able to split a 10€ bill in two 5€ bills.
For example: let's say you receive 10BTC payment. If you want to spend 1BTC you can't split it in 1BTC (paid) + 9BTC (left in address). You have to spend it all!
On the other hand, that's pretty much like paying 1BTC to someone else and sending 9BTC back to yourself. You could pay yourself to your original address, but Bitcoin-QT is smart enough to create a new (invisible to you) address which receives this change. The advantage of this "change address" is that I can no longer link your payment back to yourself:
Did you spend 1BTC and sent 9BTC as change, or perhaps spent 9BTC and sent 1BTC back as change? If you reused the same address, the change is obviously the one with the same address. If you let Bitcoin-Qt take care of it both will be new addresses and the money can't be traced back to you. This is what you meant with "the address becomes unsafe".
The key is: don't worry about this! Bitcoin-Qt will take care of all this for you! As long as you understand your accounts, addresses are disposable.
Now... what happens if Bitcoin-Qt somehow didn't send the change back to you? Imagine you just said "I want to send 1BTC out of this 10BTC" but Bitcoin-Qt forgets to send the change (this WON'T happen using Bitcoin-Qt, it's just a thought experiment).
Transaction fees are the difference between input and output, i.e. input - output. If somehow you only send 1BTC but forget to send back 9BTC of change to yourself, whoever mines this block will get the leftovers!

Thanks to you both - especially kaoD for the long answer. I was not using Bitcoin QT, but I think I under stand what you are trying to say because i do have litecoint-qt (but no money there yet).

For BitCoin I followed advice saying that a paper wallet is best as it cant be hacked. So I booted up livedvd of mint linux, stayed offline, printed 50 or so addresses using a saved copy of bitaddress.org. I have a few euros to test moving into some of these addresses. If I move 10 euros (0.0143603 BTC)to my first address then pay for something in a shop for 2 euros (0.00287414 BTC) then Do I manually need to spend the remainder to my saving address before the block gets mined which will happen inside 10 minutes. question mark.

I was trying ellectrum on linux but it feels too spartan for my taste. I dont have much confidence in trusting it to my cash at the moment.

I was also tring out multibit on windows but I dont have confidence that windows can remain secure - yes I do my online banking with windows but it has 3rd parrty security software, 3 passwords etc.

Think of it as spending a £10 note (or your local currency). You can only spend ALL the note, you can't give £2 of it to someone. What you can do is give them £2 and receive back £8 in a different form.
It's the same on bitcoin, you can only spend ALL the amount in an address. Some of that amount will go to the person you want to pay and some back to an address you control (as change). It's possible in theory to send the amount back to the original address but in practice wallets create a new address to send it to. (SOmething to do with security but I'm not sure what)


text:
Problem with receiving bitcoins on my VPS
I installed bitcoind v.0.8 on my VPS (with Debian 6 (Squeeze)). Then I generated a wallet for it: 12VWVmNEM1q6N9zMjX9aH3wSfRUbjVkZ21.
Here is my transaction to this wallet, but when I'm looking for this wallet balance with getreceivedbyaddress or getbalance I get 0.00000000. What can cause it? How can I receive my funds?

It looks like the block chain simply hasn't synced up fully for you. It usually takes a few hours to download the whole block chain and during this time the program will have inaccurate balances.
Verify your block count
Check your Bitcoind's block count with the getblockcount command and make sure it matches up with the network's block count. Heres the network block count, maintained by blockchain.info.
Make sure you're downloading blocks
If it doesn't match up, make sure your Bitcoind is atleast in the process of downloading blocks, try the command a minute later and see if it has incremented since then. If the block count stays the same number over a few minutes, it very likely that the following is your problem.
Why a server isn't downloading the block chain
Something that I've seen happen is that Bitcoind may stop downloading blocks at some point in the middle of the full chain. This happens because your server is running out of memory. Downloading the block chain is a heavy procedure because each block needs to be checked. You can remedy this by just manually moving a chain you've downloaded onto the server or get more ram (you need more than .5 gb of ram to run Bitcoind anyways). The community has the block chain available on torrent.


text:
How to move Bitcoin data from Application Support on an external drive [Mac]
I'd like to put all my Bitcoin data on an external drive instead of having it on my hard drive, as it's taking too much space on my laptop.
I did find an answer on this page regarding how to create a standalone application out of Bitcoin-Qt, but somehow that doesn't work for me. It doesn't seem to do anything different.
How can I move my Bitcoin data?

You can also use an online wallet like blockchain.info. That will take up zero space on your hard drive.

Asking about how to change the default storage location has been posted many, many times. The future canonical question is probably Bitcoin-Qt setup: Change block-chain file location, settings? documentation?. Possible duplicate of Bitcoin-Qt setup: Change block-chain file location, settings? documentation?.

Assumptions:

Your current folder for your bitcoin data is here:
"~/Library/Application Support/Bitcoin" or here
"/Users//Library/Application Support/Bitcoin"
Your current folder for your bitcoin-qt application is here:
/Applications/Bitcoin-qt.app
You have an external drive named "My Passport" and your Finder,
Preferences setting are set to display Devices.  Select Finder,
Preferences and tick the box to the left of External disks.

To do this on a MAC running OSX 10.9 follow these instructions:

Open Finder.
In Finder, using the Finder menu bar, select: Go, Go To Folder... , and type ~/Library and press the RETURN key.
In Finder, navigate to the "Application Support" folder.  You will see the Bitcoin directory.
In Finder, select, or highlight, this folder, then select: Edit, Copy "Bitcoin" from menu bar.
In Finder, navigate to your external drive "My Passport".
In Finder, create a folder called "Applications" on your "My Passport" external drive (see step "3" above after connecting external drive, if necessary).
In Finder, navigate to the newly created "Applications" directory.
In Finder, select edit and paste item to start copying the "Bitcoin" directory to your external drive's "/Volumes/My Passport/Applications/" folder.
Once this completes and both the "~/Library/Application Support/Bitcoin" and "/Volumes/My Passport/Applications/Bitcoin" folders are identical.  Rename the Bitcoin directory in  "~/Library/Application Support/Bitcoin" to  "~/Library/Application Support/BitcoinOLD".
Launch Terminal from LaunchPad, Utilities or from Applications in Finder.
At the Terminal prompt type: cd ~/Library/Application\ Support Yes, that "\" slash is necessary.
Type: ls -laf, and insure that the Bitcoin directory is now called BitcoinOLD.
Type: ln -s /Volumes/My\ Passport/Applications/Bitcoin/ ./Bitcoin.  this command actually creates a symbolic link to your external drive.   Yes, that slash "\" just after the "My" is necessary to account for the space in "My Passport".
Launch Bitcoin-qt from Applications in Finder and let the "Reindexing blocks on disk.." process complete.  It should not be downloading anything until this completes and then will download only those blocks since your last synchronize to the Bitcoin network.
Once this completes, delete the BitcoinOLD folder using finder. "~/Library/Application Support/BitcoinOLD".

You could set datadir in your bitcoin.conf to a location on an external drive. You'll still need to keep the Application Support folder there to have bitcoin.conf in it.
N.b. I have not tried this.

Thanks to your link, I finally found out why this:
http://bitcoin.stackexchange.com/questions/8837/how-to-make-bitcoin-qt-or-other-client-run-off-of-a-flash-drive-mac
didn't work for me...After I copied and renamed my original bit coin-qt app, it worked exactly it was intended to.

"All command-line options (except for -datadir and -conf) may be specified in a configuration file, and all configuration file options may also be specified on the command line. Command-line options override values set in the configuration file." https://en.bitcoin.it/wiki/Running_Bitcoin#Bitcoin.conf_Configuration_File

@Colin, Why do you say "N.B." instead of "Note:"?

https://en.wikipedia.org/wiki/Nota_bene

As of version 0.9 (not yet released, but a release candidate exists), you'll be able to choose the data location on first startup.


text:
Better or worse to mine multiple workers on one machine?
I use cgminer on Ubuntu 12.10 to mine bitcoins in the 50BTC pool. I have three workers set up. If I run multiple instances of cgminer, each targeted at their respective workers (1, 2, and 3), would this increase profits or just waste power?
I notice this because cgminer only uses about 80-90% of my GPU (Radeon HD 6570) anyway.

You ought to test the setup on the machine you will be using. Generally the mining software should efficiently use the entire GPU, but it might happen that it will not and actually running two instances at the same time will allow you to tap into more computing power. But again, check your speed while running one or more instances and see which one gives you more total speed.

Thanks, what I think is the GPU usage percentage on cgminer might not actually be the GPU usage anyway. Unfortunately, there is no reliable way to check the GPU usage in Linux distros, so I guess I'll just mine with one worker for now.

I run 2 instances of cgminers because I have two cards one which performs better for SHA256 and the other performs better for the SCRYPT algorithm.
Effectively increased my hash rate by 10 percent doing this.
The only problem is when you use --auto-fan and (presumably) --auto-gpu
The nuisance is that cgminer version 2.4.1 is trying to control the fans of the GPU card that is turned OFF which causes unwanted rapid oscillations in fan speed as 2 cgminers are trying to control the fan of a single card.
To solve that, you need to go in G(PU)/C(hange)/#/A(uto)/F(an) where # is the number of the GPU card that is set to OFF in a specific instance of the cgminer.
This will prevent cgminer from accessing the fans of the card that is turned off.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
src/net.cpp | What does "nUnkBias" define/mean
net.cpp for example:
// use an nUnkBias between 10 (no outgoing connections) and 90 (8 outgoing connections)
            CAddress addr = addrman.Select(10 + min(nOutbound,8)*10);
What does this line of code exactly mean/do?

F.Y.I.: this code has been removed (https://github.com/bitcoin/bitcoin/pull/5941) from bitcoin-core.

thx for info, found it


text:
Is there a solid "Bitcoin Bank" yet?
Once MyBitcoin was thought to be a "solid bitcoin bank". Then it was hacked and a lot of people lost a lot of money there.
Is there another, secure alternative for storing Bitcoins except storing them on your own computer?
(Obviously correctly storing Bitcoin on your computer, with proper encryption and backup, will always be more secure because you don't have to trust anyone. Still, for a lot of people, an online Bitcoin bank is a must.)

I don't think it was ever "thought" to be solid, it was pretty plainly dumb/scammy actually.

Also, storing them in your computer you have to trust someone: yourself, and whoever accesses to your computer. Encryption doesn't help if you got a keylogger.

Currently, the most secure place to store bitcoins online appears to be the exchanges. There is some evidence that Mt. Gox is also hoping to become the default bitcoin bank as they are developing mobile payment applications for instant payment.
http://mtgoxlive.com/mobile/
They have also reimbursed the losses of another bitcoin exchange.
https://www.mtgox.com/press_release_20110811.html
It is worth pointing out that while Mt Gox was hacked, no one lost any bitcoins that were not reimbursed.

Is there a public record that all funds were really reimbursed? http://bitcoin.stackexchange.com/questions/163/were-all-funds-stolen-from-mt-gox-finally-returned-to-all-users

On the semi-official forums, there are three people who claim to not have been reimbursed. I find two of their claims plausible and one of them absurd. So certainly at the very least the vast majority of people were reimbursed. It seems odd they would reimburse everyone except two people, and the amounts weren't particularly large. So I believe Mt. Gox.

It's also worth noting that Mt Gox offers two-factor authentication in the form of a Yubikey hardware token, putting them a step ahead of most online wallets in their resistance to keylogging and compromised sessions.

This answer is not quite outdated, since we have javascript clients like mywallet or strongcoin. Moreover, it doesn't take into account the fact that any bank-like site (including exchanges) might operate at a fractional reserve. Related: http://bitcoin.stackexchange.com/questions/2743/pros-and-cons-of-using-mt-gox-as-an-e-wallet

I meant "is now quite outdated".

There are a lot of online services where you can keep your bitcoins. You just need to choose what is more convenient for you, depending on what features do you need.
All Bitcoin Exchanges can hold bitcoins and some of them allow you to instantaneously transfer bitcoins between users, which can be a big plus if you want to accept payments.
Other popular ewallets include instawallet, walletbit and flexcoin. Flexcoin acts more like a real bank because it pays "discounts" (interest) to users. Tradehill is also preparing an ewallet at bitcoin.com.  blockchain.info offers an ewallet with the unusual feature that they don't have access to your private keys.
As for security, it is hard to know what is going on from the outside. Some exchanges keep part of their coins offline, which is good. Flexcoin is also planning to introduce a cold storage feature.
New services appear every day, so it is hard to point out a single big "bitcoin bank" right now. Check a few and choose one that suits your needs.

Mt. Gox is the most trusted exchange by its sheer volume, I guess that makes it also the most trusted bank.

@ripper234 Bigger sites are a much more interesting target for hackers. And MtGox has already been hacked in the past... You can't just state they are the most secure bank without knowing anything about their security measures.

Well, I'm assuming that they at least they are perceived by the public to be the most secure and trustworthy, otherwise people would have migrated to other exchanges by now.

@ripper234 I understand and I don't want to start a discussion here ;) I have made my point. Just don't forget that traders go where the volume is. MtGox is not a bank. It is the biggest exchange because it has the biggest volume. That doesn't say much about where people keep their savings.


text:
How to get destination address from bitcoinj TransactionOutput?
I believe TransactionOutput represents one of the outputs of a transaction.
I have a list of such output objects, and a String that represents my own address. I would like to check that this output reached my address.
How do I get the destination address from the TransactionOutput object?

TransactionOutput.getScriptPubKey.getToAddress.toString
Unfortunately, this gives an exception when dealing with an oldstyle pay-to-IP script, so you might have to deal with these yourself if you need them (which in your use case you probably won't). An example can be found in the Scala code from the link below (from line 120 on):
https://github.com/stefanwouldgo/Bitcoin-Graph-Explorer/blob/master/src/main/scala/Graph.scala


text:
As a small hotel accepting bitcoins, do I show only one payment address?
I am currently accepting bitcoins as payment at my hotel, but I am uncertain about the payment address(es).
I prefer to avoid payment service such as BitPay and Coinbase to mention a few.
At this moment, the idea is that when a client books a room online he receives an invoice in US$ amounts by email with the payment options. In order to confirm his booking, he can then decide to pay in cash, credit/debit cards or bitcoins and replies by email or in person. In case of bitcoins, I, as the merchant, will send him an email (or inform at the reception) with the conversion rate US$/BTC and ask the client to transfer x BTC to my address.
My preference is just to show my payment address or QR code on my website, but I would like to know the following:

Can I use the same payment address (how long?) or is it really important to create a new address for each client?
What best practises would you recommend for a legal and transparent merchant?

Suppose you go with just using one address.  Now suppose there comes a day when two different customers make reservations that have the same price. But you only get one payment to your address. Both customers claim to have paid. What will you do?

Making a new address for each transaction will allow you to follow each and every transaction made to your hotel. If you used the same address for all the transactions everything will all go to the same wallet. While if you made new wallets (if you used blockchain.info you can see that you can make new wallets or addresses within your account) you would be able to see who booked and for how much. At the end it all depends how you like it.

if you are collecting the payment with them face to face then a single address is fine. it is good because you can just print out the qr code and let them scan it.
If you are not collecting face to face then having multiple addresses is good.
Also if you want to code a price into the address then having multiple addresses is good too.
Bitpay, coinbase all help you do that.
for something really easy check out easybitz they have the quickest way.

@JonathanRogiest you can download it today and compile it..
you can play with it here.. looks neat.
https://bitcoincore.org/~gavin/createpaymentrequest.php


text:
Problem integrating Bitcoin daemon with PHP
I have installed the daemons of Bitcoin, Litecoin and Dogecoin on the same server. All three of them are up and running, but the Bitcoin daemon does not reply with anything when I run bitcoind getinfo. It may be network issues or something like that. I have installed PHP on the same server and created an index.php file in the /var/www/ folder.
Content of index.php file:
<?php
    include_once('Bitcoin.php');
    include_once('jsonRPCClient.php');
    $dogecoin = new jsonRPCClient('http://user:pass@localhost:8332/');
    print_r($dogecoin->getinfo());
?>

Content of Bitcoin.php:
<?php
    class Bitcoin (
        // @var string
        private $username;
        // @var string
        private @password;
        // @var string
        private $url;
        // @var string
        private $id;

        public function __construct($url,$username,$password)
        {
            $this->url=$url;
            $this->username = $username;
            $this->password = $password;
            $this->id = 1;
        }

        public function __call($method,$params)
        {
            $params = array_values($params);

            $request = json_encode(array(
                                       'method' =>strtolower($method),
                                       'params' => $params,
                                       'id' => $this-> id));
            $curl = curl_init();
            curl_setopt($curl,CURLOPT_RETURNTRANSFER, 1);
            curl_setopt($curl, CURLOPT_HTTPHEADER, Array("Content type:application/json"));
            curl_setopt($curl, CURLOPT_URL, $this->url);
            curl_setopt($curl, CURLOPT_USERPWD, $this->username.":".$this->password);
            curl_setopt($curl, CURLOPT_POST, TRUE);
            curl_setopt($curl, CURLOPT_POSTFIELDS, $request);
            $response = curl_exec($curl);
            curl_close($curl);

            if(!$resposne)
            {
                throw new Exception('Unable to connect to '.$this->url, 0);
            }
            $response = json_decode($response,true);
        }

        Then there are a condition to throw a different error upon a different situation.

    }

@peter-mortensen that extra lines are just to avoid typing all the exceptions it was not like this in the actual file

Howdy?
Ok I was searching for tutorials all over internet on "how to integrate bitcoin daemon with php" I came up with many and none of them helped me to get it working flawlessly, some of them threw unexpected and strange errors after 90% completion and some of them good enough to throw error in starting only which saved my time and efforts. Now that I have done what I was looking for why not create a step by step tutorial to help fellow members. So let's get started.
Before we start you should install tmux which helps you save your work even if you are disconnected from the vps. To install tmux:
sudo apt-get install tmux

to start tmux simply type tmux and to get back on mai screen press ctrl b and then d to restore the session again type tmux attach.
I am expecting you have a Ubuntu 12.x or later because that is what i used for installation. Log in to your VPS or your computer's terminal and install python software properties by typing following command :
sudo apt-get install python-software-properties

then add repository ppa:bitcoin/bitcoin by typing following command
sudo add-apt-repository ppa:bitcoin/bitcoin

In my case this didn't work and threw an error stating that add-apt-repository command not found. In ubuntu later version versions this command is not found under python-software-properties package, like in previous versions, but available in software-properties-common. So I had installed it by running these commands :
sudo aptitude install software-properties-common

To find in which package the command we are looking for exists the following will be of help:
sudo apt-fille update

Unfortunately in my case this was also not installed so I had installed it by running following command :
apt-get install apt-file

Now I got the message "The file is up to date"
Now run
    sudo apt-file search add-apt-repository
You will be prompted to confirm this installation, press Enter key to confirm.
Now run
sudo aptitude update

and then
    sudo aptitude install bitcoind
Make a new directory by typing :
mkdir ~/.bitcoin
cd ~/.bitcoin

Create a new file inside this directory named bitcoin.conf by typing:
    nano bitcoin.conf
insert the following code in the text file:
server=1
daemon=1
rpcuser=any_username
rpcpassword=any_password

Exit by pressing ctrl+x to confirm the changes press Y and then press return key. Start the bitcoin daemon by typing:
bitcoind

Bitcoin daemon is now installed and runing you can check it by running the following command
bitcoind getinfo

Now we will install apache and php on our server
To install apache we will run th following code:
sudo apt-get install apache2

once apache is installed verify it by typing your ip address in the browser it will say It works!
now we will install php by following command:
sudo apt-get install php5 libapache2-mod-php5

now navigate to var/www folder and download jsonRPCClient.php with the following command:
wget http://pmtocoins.com/JSON-RPC_PHP_light.zip

once downloaded unzip it by typing:
    unzip JSON*.zip
no move to the directory by:
    cd json*/includes
and move jsonRPCClient.php into your www folder
now create a new index.php file in www folder with following code
<?php
include_once('jsonRPCClient.php');
$bitcoin = new jsonRPCClient('http://your_username:your_password@127.0.0.1:8332/');
print_r($bitcoin->getinfo());
?>

and you are done navigate to your ip address on the browser e.g 161.232.12.1/index.php
You can have a look on API call list here : https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_Calls_list

.
You can use Open Source Bitcoin-PHP Payment library -
https://github.com/cryptoapi/Payment-Gateway
    <?
        require_once( "cryptobox.class.php" );

        $options = array(
        "private_key" => "",        // private key from gourl.io
        "orderID"     => "your_product1_or_signuppage1_etc",
        "amountUSD"   => 2          // 2 USD
        );

        // Initialise Payment Class
        $box1 = new Cryptobox ($options);

        // Display Payment Box or successful payment result
        $paymentbox = $box1->display_cryptobox();

        // A. Process Received Payment
        if ($box1->is_paid())
        {
            // Your code here to handle a successful cryptocoin payment
            // ...
        }
        else $message .= "The payment has not been made yet";
    ?>
    <!DOCTYPE html>
    <html><head></head>
    <body>
    <?= $paymentbox ?>
    <?= $message ?>
    </body>
    </html>

This doesn't solve the asker's problem. He wants to communicate with his own Bitcoin daemon


text:
Can the transaction log history size scale?
Four Reasons You Shouldn't Buy Bitcoins, Forbes.com:

Scaling. The Bitcoin protocol requires that every node in the network
  download a copy of every Bitcoin transaction that has ever occurred.
  As Bitcoin has grown more popular, running the “full” Bitcoin client
  has become more and more resource-intensive. The last time I started
  up my Bitcoin client, it took several hours to download all the
  transactions that had occurred in the few weeks since the last time I
  ran it.
To prevent things from becoming completely unwieldy, the Bitcoin
  protocol limits the size of each “block,” the basic unit of Bitcoin’s
  shared transaction register, to one megabyte. Since one block is
  created every 10 minutes, on average, this places a hard limit on the
  number of transactions the network can process each hour. Right now,
  the network is operating well below the limit. But it’s not that far
  below the limit. If the Bitcoin economy continues to grow rapidly,
  we’re likely to hit it in the next few years.
Reaching the limit wouldn’t be catastrophic; the Bitcoin protocol has
  an elegant system of transaction fees to process the most urgent
  transactions first. But it does place some limits on Bitcoin’s
  long-term future. For example, it’s hard to imagine Bitcoin ever
  becoming a replacement for conventional credit cards. There are far
  too many credit card transactions for the Bitcoin network to
  accomodate.

Currently, every Bitcoin client knows the entire network history. This sums up to a few GB, which a modern computer can easily hold.
The number of transactions, however, is growing quickly. I roughly estimate than in a matter of a year or two, the total size on disk will exceed the abilities of a normal desktop computer.
How will the network function when the transaction history log grows beyond the powers of a normal desktop?

No, this isn't a likely problem for Bitcoin. Or, to be more specific, it is a problem that there known ways to solve.
First of all, there is a concept called a selfish client. Which means a client that can create and receive transactions, but doesn't maintain the blockchain. It's considered "selfish" because it isn't performing the work expected of a true node on the system: it only maintains the information needed for it's own transactions. These types of clients are already common in the mobile world today, where 8GB is already too much to handle.
But if we got to a scenario where the blockchain was too unwieldy for the typical client, we would also probably be in a scenario where the network already had a sufficient number of server nodes to handle the "network".
Second, Bitcoin already has the concept of discarding transactions once they are spent. (It is made possible by the way that transactions are stored in the block: via the Merkle tree.) It is essentially not implemented yet, but the concept is there for when it is needed.
It's not inconceivable that we might end up with three tiers of clients: selfish clients on our mobile devices, master nodes that have all of the transactions and can trace any transaction ever made, and hybrid nodes that do support the entire Bitcoin protocol but only keep a trimmed version of the blockchain that prunes transactions that have already been spent. See this question for some details about pruning : Is pruning transaction history implemented in Satoshi's bitcoin client? .

I lament that I have but one upvote to give this stellar answer.

I thought this had been answered before, but I couldn't find the duplicate. Thanks for the kind words.


text:
Can I use a passphrase as a private key?
Is there a way to use a long (and possibly hashed) passphrase as a private key, so that all I need to recover my Bitcoins would be that password?
I was thinking of buying Bitcoins using a private key that's generated from a passphrase, and then deleting the Bitcoins software entirely. When I want to use my Bitcoins in the future, I will re-create the key using the password. This will eliminate the possibility of stealing my Bitcoins by hacking to my computer.

Be aware that when you do this, you expose your wallet to the entire world to do a brute-force attack on your password. If many people start doing this, it may become very profitable to try to find their passwords. Software like Armory and Electrum have the ability to generate a determinsitic wallet from a 'seed', but this seed is still randomly generated, in order to be sure that it is hard to attack.

The simplest and most common way of doing this is to do SHA256(passphrase) and to use the result as your private key. You can e.g. use the "Brain wallet" tab on www.bitaddress.org which is all javascript so that you can download it and do everything offline for increased security.
Be aware though that your pass phrase must be really long and truly unique since if someone would use the same pass phrase they would have access to your money. The comment from Pieter Wuille above is worth repeating:

Be aware that when you do this, you expose your wallet to the entire
  world to do a brute-force attack on your password. If many people
  start doing this, it may become very profitable to try to find their
  passwords. Software like Armory and Electrum have the ability to
  generate a determinsitic wallet from a 'seed', but this seed is still
  randomly generated, in order to be sure that it is hard to attack

To put some numbers on how long and unique it has to be, to be confident in its security, you should pick a passphrase such that an attacker would be expected to need to guess at least a billion billion passphrases before he'd come up with yours. For example, a passphrase that would probably be considered just barely strong enough would be firefly 80 m00se!

You ought to look into solutions such as Brainwallet. It hashes your passphrase into a Bitcoin address.

Yes, you can. It's named Brain Wallet but... Both answears (@ThePiachu and @D.H.) lead you to catastrophy. Don't use external tools to create your brain wallet. Do it on your own on your PC disconnected from Intenet. There is a lot of tools to count SHA256 on your own. When you creating your passphrase use not only alphanumeric characters but also other.


text:
Data directory issue
I have everything set up normally. My only issue is that my data directory is in C:\Users\User Name\AppData\Roaming\Bitcoin.
Normaly this is what you would want, but, if you noticed, my username has a space in it (obviously I changed it for privacy) so when I try to designate my data directory in the miner program it says the directory does not exist because the space in my username causes the directory link to break ( C:\Users\User ) instead of the full link...
Is there a way I can change where Bitcoin-Qt stores its data by default?
And no, a re-directory won't work, because it can't find the location in the first place.

I was having disk space problem, so I installed it in E:
I created a separate directory for storing data first.
Then, I created a shortcut to bitcoin=qt.exe on my desktop and added the parameter in the target as described above. Now it's working fine, thanks.

Asking about how to change the default storage location has been posted many, many times. The future canonical question is probably Bitcoin-Qt setup: Change block-chain file location, settings? documentation?. Possible duplicate of Bitcoin-Qt setup: Change block-chain file location, settings? documentation?.

possible duplicate of Bitcoin-Qt setup: Change block-chain file location, settings? documentation?

Run bitcoin with the parameter -datadir=C:\New\Dir
E.g. create a shortcut and change "target" to "C:\Program Files (x86)\Bitcoin\bitcoin-qt.exe" -datadir=C:\BitcoinData

where do i go to add the parameter?

ok i created a shortcut for bitcoin-qt and i added -datadir=C:\BitcoinData to the end but it just says C:\BitcoinData doesnt exist

issue solved, i changed my Username via another admin account and regedit to change the log in defaults

-datadirC:\BitcoinData as strange as it is, do not put no nothing between datadir and your dir.....