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1answer
767 views

Fraud Detection & Prevention

What are controls that are in place to detect and/or prevent fraud within the bitcoin system? Are there any know exploits, or potential threats to the system?
9
votes
2answers
427 views

Is there a chart of Bitcoin merchants over time?

Does there exist a chart documenting the number of bitcoin merchants over time, and if not, would it be possible to create one from any available data source? (I'm thinking mostly of https://en....
8
votes
1answer
1k views

How to debug a failed restore of a Namecoin wallet?

I bought some Namecoins a while back. With the upcoming Merged Mining patch, I reinstalled Namecoin 0.3.24.63 on my newly formatted computer, copied my wallet.dat from my backup to the right folder, ...
12
votes
3answers
6k views

Is there a usable Namecoin GUI client?

Is there any GUI client that is capable of trading Namecoin, and is somewhat trusted by the community?
-1
votes
1answer
5k views

Bitcoin Client says transaction is unconfirmed for 2 days now [duplicate]

Possible Duplicate: How to debug a long “0/unconfirmed” status in the bitcoin client? I made a transaction two days ago, but blockexplorer.com doesn't show the recipient address. Also ...
2
votes
1answer
768 views

How do the clients agree on the target to hash for? [closed]

Edit: They do not agree on a specific target hash. Any hash lower than or equal to the difficulty is sufficient. This means clients only have to agree on difficulty.
16
votes
3answers
477 views

What happens if the developers make a controversial change to the “standard” client?

One criticism I commonly hear of Bitcoin is that it merely transfers trust from some sort of central bank or government entity to the developers of the main project. Can anyone provide a clean ...
15
votes
5answers
1k views

How would interest and fractional reserve banking work in a limited money supply?

Suppose Bitcoin lenders (banks, creditors, investors) issue loans with interest. As the total supply of bitcoins approaches the 21M ceiling, the total amount owed in outstanding interest will exceed ...
56
votes
3answers
66k views

How to calculate transaction size before sending (Legacy Non-Segwit - P2PKH/P2SH)

I know that I pay the transaction fee per kB, so how can I calculate how large the transaction will be before I send it via the RPC api. I run a site using bitcoins, and I cannot let the user's ...
7
votes
3answers
735 views

What does TruCoin do?

I just saw that Gavin is employed with a company called TruCoin. Any idea what does it actually do besides help develop and QA the bitcoin client? The about page (odd URL) doesn't explain it much.
15
votes
1answer
974 views

Would a reduced block generation time make the Finney attack more difficult?

Related Question: What can be done to mitigate the risk of a Finney attack? The Finney attack is a form of double-spending attack where the attacker pre-mines a block containing a conflicting ...
11
votes
1answer
3k views

What strategies can an e-wallet use in order to reduce transaction fees?

I noticed that most Bitcoin exchanges (MtGox, TradeHill, ExchangeBitcoins, etc.) do not charge any fees for withdrawing bitcoins. What kind of strategies can they use in order to reduce these costs?
11
votes
3answers
675 views

What can be done to mitigate the risk of a Finney-attack?

Related Question: Would a reduced block generation time make the Finney attack more difficult? I understand that the Finney-attack is the main reason why accepting a zero-confirmation transaction ...
9
votes
4answers
3k views

Is there a “MtGox Live” alternative which supports Euro?

MtGox Live is a quite pretty live market depth graph. For some reason it only shows prices in USD. Does anyone know an equally good alternative which supports EUR instead?
109
votes
5answers
19k views

Why is 6 the number of confirms that is considered secure?

Why is 6 is the number of confirmations that is considered secure? I haven't found any mathematical explanation or otherwise that explains why it is 6 and not 5 or 7. Is there a historical reason for ...
10
votes
3answers
4k views

What software/hardware is required to mine with an FPGA?

I have been looking for a device that would allow me to mine Bitcoins without too much noise and heat. Something relatively small that I could keep in a shelf without worrying too much about it. A ...
12
votes
7answers
3k views

Are there any poker websites that accept bitcoins?

I would think that bitcoins would be a great fit for websites that allow for gambling, and with Texas Hold 'em being such a big card game it seems that a Hold 'em site might allow players to use ...
9
votes
2answers
1k views

How can determine the fundamental theoretical value of the Bitcoin based on steady state daily velocity (BTCDD)?

The VISA network (VisaNet) supports 4.4 Trillion dollars of commerce per year (2009). If we assume (somewhat arbitrarily), that the Bitcoin Days Destroyed metric approaches 50% (half of all coins are ...
13
votes
6answers
6k views

How to debug a long “0/unconfirmed” status in the bitcoin client?

When someone gets a status of "0/unconfirmed" on a transaction for a long time - what could he be doing wrong? What should he check to solve this?
9
votes
2answers
1k views

Merkle Tree hashing

I'm trying to implement my own Markle Tree, currently I'm working on getting the hashing done correctly. I've used some hashes from http://blockexplorer.com/rawblock/...
12
votes
1answer
373 views

If Bitcoin is ratified as a currency would its code be BTC?

At present it seems that the de facto code for bitcoins seems to be BTC. There has been some discussion of this over on the forums and an entry on Wikipedia, but I thought I'd ask the question here to ...
8
votes
1answer
803 views

Services paid in Bitcoin [closed]

I am interested in what other internet and other communication services out there are accepting Bitcoins for payment. I know of http://mullvad.net/ for VPN and a few others, http://www.chundle.com/...
8
votes
2answers
661 views

What does a comparison of Bitcoin Days Destroyed say about Bitcoin vs Namecoin vs SolidCoin?

The Abe blockchain explorer provides statistics for percentage bitcoin days destroyed, using the generic term "% CoinDD". Currently Bitcoin is 36.1245%, Namecoin is 41.5547%, and SolidCoin is 47.0952%...
0
votes
1answer
76 views

Best way to get the OID of an order created at TradeHill?

I'm working on my first trading script using the TradeHill API. I find it pretty annoying that the OID of an order isn't returned to you when you create a new buy/sell order. How exactly can you get ...
0
votes
2answers
877 views

Costing arbitrage between exchanges [closed]

I'm currently writing something to script arbitrage between two exchanges to test the concept. I know I can determine the difference in prices by using (ExhangeA_sell - ExchangeB_buy) <- this ...
22
votes
3answers
12k views

How do I implement a Merkle Tree?

I`m slowly implementing some Bitcoin protocols, and I'm not sure how to properly understand the Merkle Tree from the Bitcoin wiki: https://en.bitcoin.it/wiki/Protocol_specification#Merkle_Trees I have ...
6
votes
4answers
268 views

Can new types of transactions be included the current block chain?

I was putting an answer for this question together when I realised my idea would require a new type of transaction to be invented and included in blocks. Then I wondered how that could work. There ...
5
votes
5answers
656 views

Could a futures market be included in the Bitcoin protocol?

One of the most common reasons I hear that Bitcoin is "not ready for prime time" is that because of its wildly oscillating valuation businesses can't accept bitcoins without becoming speculators. In ...
4
votes
3answers
227 views

Can a bitcoin transaction be used to send usernames?

I'm looking to implement a secure mobile messaging service and looking for a payment system that will allow users to buy message credits and have them be allocated to a specific account however I want ...
9
votes
4answers
309 views

String-along, is this possible and is it an attack?

I haven't seen this discussed before, if it has been please provide a link. If I find a block while mining but then discover that another miner broadcast a block mere moments ago, I could begin ...
9
votes
2answers
333 views

Standing Orders, Is it possible with Bitcoins?

Is there a service out there, or is there any intention to integrate Standing Order type transactions into the client ? (Every 30 days transfer 0.2BTC to a specific address for example).
27
votes
5answers
2k views

How much would it cost to execute a 51% attack?

I know that it's commonly said that they're not really in the realm of possibility right now, but how much would it really cost to execute a 51% attack on the network? And are there any organizations ...
7
votes
1answer
484 views

How should centralized wallets handle user accounts?

I tried to generalize this question from one I asked on the BitcoinJ development list. I'm working on a project that requires a centralized wallet. From what I gather, these types of services ...
9
votes
3answers
419 views

Is there any consensus over specific improvements Bitcoin needs?

There has been some criticism from cryptography experts about the current Bitcoin algorithm(s). Now that Bitcoin has been released to the wild and everyone has had time to study it, is there any ...
45
votes
6answers
6k views

What unique business models has Bitcoin enabled?

Are there specific, unique business models that have been made possible by the invention of Bitcoin? And if so, what are they? Edit: I seem to be getting a lot of answers about the areas of ...
36
votes
8answers
4k views

How to save bitcoins as paper?

I would like to save some of my bitcoins on a piece of paper with QR code printed on it. What would be the easiest way to do it without using Mt Gox. or similar. Just bitcoins (I'm not afraid of some ...
40
votes
2answers
6k views

What is the coin selection algorithm?

When creating a transaction in the standard client, what is the algorithm used to determine which unspent outputs will be used as inputs? Has this changed since the first version? What different ...
5
votes
1answer
570 views

How are transactions in discarded forks merged back into the blockchain?

It sounds like transactions in discarded blocks are propagated back to the network to be included in the next block to be generated, is that the case? If so, is that triggered in the client when it ...
-5
votes
1answer
381 views

What are the dangers of MtGox's trademark over Bitcoin? [closed]

If anyone trademarks bitcoin, shouldn't it be Satoshi, Gavin or one of the people who actually made it instead of some exchange site that's trying to profit from it and faces competition from other ...
6
votes
3answers
9k views

Do bitcoin miners actually make money [duplicate]

Possible Duplicate: How can I compute mining profitability? Do bitcoin miners like the one depicted in the video below with 24 server clusters actually profit from bitcoins at the current prices? ...
22
votes
2answers
5k views

Could the EC2 infrastructure be used to efficiently launch a 51% attack?

This excellent answer from Serith states that one would need 31150 ATI 5870 graphics cards to launch a 51% attack. Amazon EC2 offers computers for rent for 2.10$ per hour. These instances have 2 x ...
20
votes
4answers
3k views

Can a 51% attack be detected and dealt with?

If someone got 51% hash power and started rewriting the blockchain from scratch (building a longer chain with a completely different history), could this be detected? Could "the honest users" revert ...
4
votes
2answers
644 views

How many consumer computers would it take to launch a 51% attack [closed]

What is the hash rate of a standard laptop using the default client and what is it for the whole of Bitcoin? I am interested in this, because I want to understand what it would take to get to 51% of ...
15
votes
1answer
2k views

What is the “zeitgeist attack”? Does it affect all blockchain technologies?

What exactly is this attack? It would be nice to have a good explanation of how it works and which chains can be effected by this. Does it apply to the bitcoin main chain, or only the newer and ...
8
votes
5answers
892 views

Would it be possible to patent Bitcoin?

Bitcoin utilizes a proof-of-work mechanism to assure against double-spending, as well as providing an example opensource implementation. However, some countries allow software patents, which could ...
5
votes
1answer
165 views

What OSes don't yet have Bitcoin clients?

Bitcoin has clients created for many OSes already, but which (semi-)significant operating systems don't yet have a Bitcoin client created for them? Is there some opensource code I can use as a ...
16
votes
5answers
2k views

What can xxxCoin do to stop the impending 51% attack?

Within the coming weeks both Namecoin and SolidCoin have been threatened with the same attack. What can be done by the users, pool operators and developers of these forks to either; A. Minimise ...
-1
votes
1answer
121 views

Gui shutdown: message in the terminal [closed]

I closed down bitcoin from the official gui client with File > Exit and the following message appeared in bash: ************************ UNKNOWN EXCEPTION bitcoin in CMyApp::...
10
votes
1answer
749 views

What happened with MtGox on 2011/9/12?

On that date, some erratic out-of-spread trades appeared on MtGox. The explanation given says that accounts may have been compromised by the CosbyCoin attack on bitcointalk.org. I do not understand ...
14
votes
1answer
2k views

Why is MtGox trying to trademark “Bitcoin”?

Someone on the #mtgox IRC channel pointed me to this. It seems to be an application by Tibanne Co. Ltd. for the Trademark name BITCOIN. I asked MagicalTux on #mtgox about it, but got no answer. Why ...

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