Questions tagged [blockchain]

This tag should be used for questions pertaining to the blockchain. The blockchain is a list of all transactions that have occurred using the Bitcoin currency. It consists of blocks which are linked to each other, and each block consists of transactions. DON'T USE THIS FOR THE SERVICE NAMED 'blockchain.info'!

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13
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2answers
697 views

Have there been attempts at a Bitcoin-powered general purpose database?

https://en.bitcoin.it/wiki/Bitcoin-Powered_Database As far I know, the Bitcoin blockchain is pretty much the only data structure that is both global and tamper-proof. global - There is one global ...
8
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3answers
1k views

Does mining a block force others to restart their work?

Does mining a block mean that anyone else who was working on mining a block loses their progress and must restart?
6
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1answer
806 views

Can I run p2pool with a thin bitcoin client?

Everytime I restart my mining machine due to heat, I have to wait the following sequence to mine at p2pool: bitcoind -> download blockchain & rescan -> p2pool -> download shares -> ...
6
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1answer
2k views

What order do transactions appear in a block? Is it up to the miner?

It seems to be random or up to the miner from what I can tell. But to store blocks, one must keep the order of the transactions (in some position column, etc) because regenerating the block for later ...
6
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1answer
1k views

What does a double spend look like?

What does a double spend look like? Can anyone link to an example on blockchain.info? Will invalid half of the double spend simply remain at 0-confirmations, or might it ever reach 1 or 2? Will the ...
12
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0answers
2k views

How can an earlier block have a later timestamp? [duplicate]

Block #180966 has a timestamp of 2012-05-20 23:02:53. Block #180967 has a timestamp of 2012-05-20 23:02:13. How has the software permitted a later block to have an earlier timestamp than its ...
2
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1answer
253 views

What will be required to increase the “soft” 500KB per-block data limit

We've alerady hit the point where a block has become 90% full, thanks to the popularity of SatoshiDICE. The limit can be increased from the 500 KB max per-block in the software to 1 MB per-block ...
0
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2answers
738 views

Bitcoin client only has 1 connection? [duplicate]

I have had bitcoin for a little bit now. It has been going very smoothly. I have set up 3 accounts for various activities, privacy, and security reasons. I now can not get all of the block chain. ...
4
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2answers
452 views

What is the highest recorded difficulty in the main net? [closed]

What is the highest recorded difficulty in the main net and which blocks was it used for?
7
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4answers
8k views

How can one download the initial Blockchain data files securely?

I see several sources for binary downloads of the Bitcoin blockchain. Can any of these be used securely?
1
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2answers
399 views

Bitcoin client 0.4.1.1 stuck at block 176947

Bitcoin client stuck. Tried to rebuild whole blockchain, but it went up to that number and got stuck again. Here's a screenshot: http://vvcap.net/db/2IR75OWyJj5AsUW7eo_i.htp Any suggestions?
9
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2answers
3k views

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 ...
12
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1answer
3k views

Has any illegal data been saved in the Block Chain?

Has any illegal data been saved in the Block Chain, such as an illegal number, or illegal prime?
5
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2answers
992 views

Read only blockchain in bitcoind , patch ideas

This question is related to to the ( already nearing 2 GB and always increasing size ) blockchain download needed to use the bitcoin network, and is referencing this previous question : Is "...
5
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1answer
356 views

How did these 3 tx make it into a block in the main chain?

http://blockexplorer.com/block/000000000000051b42fd09195c75da7a084df7593f47ad18139cdc9cd83a112e The last three tx have a inputs with script_sig "1". This is invalid right? According to protocol ...
8
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2answers
461 views

Bitcoin client behavior in event of a fork

What happens when a forked chain becomes longer than the main block chain? Let's assume the forked chain that just became longer has no transactions in it, so it is as if every transaction in the ...
4
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1answer
470 views

Is proof-of-stake a viable alternative / augmentation to proof-of-work? [closed]

Meni mentioned Proof of Stake as a possible way to augment Proof of Work as the underlying mechanism powering Bitcoin confirmations. Is it viable? What are its downsides? Who has analyzed it? (I don'...
10
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2answers
2k views

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?
7
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1answer
6k views

Checking pending (not yet in the blockchain) transactions

Is there a service (like Blockexplorer) that shows pending transactions that have not (yet?) been included in the block chain?
2
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2answers
740 views

How would one inject a blockchain fork to the Bitcoin network?

For theoretical purposes, how would one inject a blockchain fork in to the Bitcoin network? For example, lets say we have a small chain of blocks prepared in a program that is not a standard client / ...
7
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3answers
5k views

Cache the Bitcoin Datadir to Improve Performance? Increase Bitcoin DB Cache Size?

Bitcoin is very disk-intensive and that slows it down. It seems to flush data to disk often thus preventing proper caching. With the datadir on a RAMdisk it is much faster. Is it possible to increase ...
5
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4answers
9k views

What can I do when the blockchain synchronization is stuck at a specific block?

I hadn't started/used my Bitcoin client for ages. Now, whenever I start the client, it is downloading block 135407 and does not progress past it. What can I do?
6
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3answers
228 views

Are competing blocks a problem to weak participant of the network?

Let's say Alice has two CPUs, and Bob has only one. Let's assume Alice and Bob are the only miners in the Bitcoin network. What will happen if Alice did the following: Calculate the nonce for the ...
4
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1answer
234 views

Who obeys discouraged blocks?

I just found this gem - Discouraged Block. It proposes a method where miners "will" (are requested to?) ignore chains with certain blocks at the tip. It's not like anyone can dictate the behavior of ...
6
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2answers
3k views

Why does the initial blockchain download get stuck part way through?

I am trying to get Bitcoin up and running on a fairly underpowered laptop and Windows Vista using Bitcoin-Qt 0.5.0.1. After installing and starting the program, I am stuck at at the syncing stage at ...
27
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2answers
8k views

How many Bitcoin addresses are/have been carrying a balance?

Bitcoin addresses can be generated at will, and the theoretical limit to their number is high. Addresses are constantly being generated to receive funds or balance transactions, but they are also ...
30
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2answers
6k views

Are there any studies into the size of the blockchain scaling over time?

After watching some of one of the 28c3 talks, It got me thinking about just how scalable Bitcoin really is. With the size of the blockchain currently, given the number of transactions/users, will the ...
3
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2answers
876 views

Can you run P2Pool without having to keep the blockchain updated?

I'm guessing the answer is no, but I thought I'd ask anyway. I'm running my miner off a USB pen at the moment and I'd like to run P2Pool but the main issue for me is there wouldn't be enough space ...
3
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2answers
841 views

Can I get an overdraft?

Hypothetically... A uses a desktop bitcoin client, who would like an overdraft facility. B has lots of bitcoins and would like to offer that overdraft and charge interest on the overdrawn amount. ...
11
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2answers
4k views

What are the key differences between different ways of embedding messages in the blockchain?

Are some possible ways to embed messages in the blockchain better in some sense than others? What are the important differences? (Followup on this answer)
4
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1answer
946 views

How to decode messages embedded with btcmsg?

btcmsg seems to be using proprietary software to encode and decode messages in the blockchain. Did they expose their algorithm? If they shut down tomorrow, how can someone decode messages he stored ...
3
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2answers
1k views

Did Satoshi object to embedding data in the block chain? Why?

From this post: Our beloved Satoshi is on record that he doesn’t think it appropriate to embed data willy-nilly in the block-chain Is this claim true? If so, why did he object? I don't think it'...
17
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2answers
3k views

Is “Reclaiming Disk Space” already implemented? How effective will it be?

Some people are concerned about the scalability of Bitcoin. The blockchain already has reached nearly 1 GB to download and store, which is not exactly in the spirit of a modern thin client, especially ...
11
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4answers
724 views

Does the bitcoin block contain minimal transaction detail? (Is it as private as possible given the proof-of-work design?)

From https://crypto.stackexchange.com/questions/508/could-one-prevent-double-spending-in-decentralized-digital-currencies-like-bitc "Now, the only information about the transaction that needs to be ...
6
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2answers
5k views

How can I copy the blockchain from my working client for use with a live CD savings wallet?

I have the Bitcoin client installed on my Windows PC, but I want to set up a savings wallet with better security that I access with an Ubuntu live CD. I don't want to have to download the entire ...
10
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1answer
385 views

Is EFF's proposed Sovereign Key system similar to how Namecoin/Bitcoin works?

To avoid the problems caused by the current SSL certificate infrastructure, the Electronic Frontier Foundation has proposed Sovereign Keys, which appears to be backed by a distributed, append-only ...
16
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1answer
980 views

Peergroup download of the blockchain stalls?

I'm using bitcoinsharp to build my client. I try to download the blockchain in a peergroup network. Download starts, but when progress is 98%, the download is stopped & the client is waiting (2 ...
17
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3answers
27k views

Knowing a single transaction can you track down a Bitcoin user?

I have used this transaction to donate to Wikileaks. I have applied no special techniques to obsure my identity. How much information can find out about me on the blockchain. What tools would you use? ...
10
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2answers
1k views

Does block validation get more difficult as the blockchain grows?

I just downloaded Bitcoin 0.5 and started downloading the blockchain from scratch. The process was rather fast early on but slowed down noticeably later. That could of course be related to network ...
7
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1answer
203 views

Is the time a transaction was done recorded in the block chain?

Is there something like a timestamp of each transaction recorded in the block chain, or only the mere fact that the transaction was done?
4
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3answers
1k views

Limit size of data files

As the mere size of the constantly changing data file tampers with my backup concept, I would like to ask if there is a way to split this file into many smaller pieces. I have no problem with the size ...
25
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2answers
7k views

What is the block maturation time?

I was reading the wiki article about the blockchain and I didn't understand the part in bold: When a block becomes an orphan block, all of its valid transactions are re-added to the pool of ...
8
votes
1answer
1k views

Where can I see the average transaction fee payed in the last 100 blocks?

Is there a site that shows what's the average transaction fee payed in the last X blocks? Or just raw data about this? I checked BlockExplorer and Sytes and they don't seem to show this information.
9
votes
1answer
224 views

One dataset for many wallets… how?

It takes a while to download and process the transaction log. Doing that for dozens of wallets would be a big waste. I want to run just one client full time as a log processor. Then for each wallet, ...
15
votes
1answer
1k views

How can a non-miner store data in the block?

If I am not a miner and would like to put arbitrary data in the block chain, is there currently any method or protocol to get a miner to add it for me?
8
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2answers
2k views

Are private keys published to the blockchain after spending coins from a wallet?

Always I spend coins the final balance of the address that is used for transaction will go to zero. The remaining coins comes back as a change to a new address. Will this indicate that the private key ...
37
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3answers
9k views

What are checkpoints?

I often read that checkpoints protect the network from a 51% attack because an attacker cannot reverse transactions made before the last checkpoint. How exactly does this checkpoint mechanism work? ...
28
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5answers
3k views

What would happen if a portion of the Bitcoin network was separated from the rest of the network?

Yesterday I asked a question over at SuperUser, so that I could have my facts straight before asking this question. The scenario sets the basis for this question. Regarding bitcoin, what would ...
8
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2answers
765 views

Why isn't there a fast blockchain update inside a LAN behind a router between two Bitcoin clients?

This is the scenario: 2 computers on a LAN with private IPs (192.168.X.X) router forwards port 8333 only to one of them (the 2nd one). one computer has the full blockchain updated in its Bitcoin ...
43
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8answers
98k views

Where are the user's bitcoins actually stored?

On the person's computer? On bitcoin.org? :) Where does that information reside that tells others and me how much bitcoins I have? I assume it can't be on my PC because I could easily hack the file ...