Questions tagged [blockchain-fork]

This tag should be used for questions regarding any split in the Bitcoin blockchain

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60
votes
5answers
27k views

What is a soft fork?

When people talk about possible changes to how Bitcoin works they sometimes say a particular change can be implemented as a soft fork. What does that mean? How does this compare to a hard fork?
47
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2answers
10k views

What is the longest blockchain fork that has been orphaned to date?

The orphaned blocks view from BlockChain.info shows a recent fork of the blockchain (starting with block 173,928) that went four blocks long before being orphaned. Other than the controlled rewind ...
43
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2answers
17k views

What happens if two miners mine the next block at the same time?

The process of mining as described in the answer to this question is simultaneously repeated by multiple miners. Is it possible for two miners to find the next block at the same instant? If it is, ...
10
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1answer
4k views

Strongest vs Longest chain and orphaned blocks

Satoshi writes at the bottom of page 3 of his white paper that "If two nodes broadcast different versions of the next block simultaneously, some nodes may receive one or the other first. In that case, ...
19
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2answers
3k views

How does a client decide which is the longest block chain if there is a fork?

Is it only the block height or is it the effort that went into the forks? In other words: does this decision account for different difficulties?
25
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1answer
14k views

What is a hard fork?

When people talk about possible changes to how Bitcoin works they sometimes say a particular change would require a hard fork. What does that mean? Can a hard fork cause problems?
5
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2answers
2k views

How is a blockchain split resolved?

Let's say two miners created 2 different blocks and broadcast them into the network. Now some clients see blockchain 1 and other blockchain 2 which are different from each other. I would like to ...
12
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3answers
13k views

How to claim Bitcoin Cash & Bitcoin Gold from paper wallet

Before the first Bitcoin fork (August 1st) I put all my Bitcoin into a paper wallet. I kind of forgot about it. Now I think I can claim Bitcoin cash as well. Now there has been another fork resulting ...
45
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1answer
13k views

How does Bitcoin Cash implement replay protection?

Bitcoin Cash says that they are providing replay protection for their fork. How does this replay protection work?
11
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1answer
6k views

What is SPV mining, and how did it (inadvertently) cause the fork after BIP66 was activated?

I'm curious to hear an in-depth explanation of the hard fork and how it was caused; I've heard/read a great deal but I'm lacking a cohesive explanation.
18
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3answers
1k views

Countrywide Internet isolation, inevitable fork

Many countries around the world have provisions for shutting off the Internet as well as isolating itself from the Internet (where networking within borders still flourishes), any transaction ...
10
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3answers
3k views

What is the best way to prevent replay attacks in the event of a bitcoin hard fork?

I originally thought it would be relatively simple to add replay attack protection (change something about how the tx hash is generated) in the event of a fork. But the BU folks mentioned that this ...
8
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3answers
15k views

What happens to my bitcoins if a hard fork occurs?

It seems that on August 1st, there will be a hard fork on Bitcoin. This will mean that instead of 1 coin we will end up with 2. Without going into the discussion about whether it will or not occur. ...
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
7k views

In case of the Bitcoin split - when holding BTC on blockchain.info - will I receive coins on both forks?

Everyone says: If you do not hold private key to your BTC, you do not own BTC. Technically speaking I do not hold the private key, but I do have the 12 words backup phrase. I would like to know ...
16
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1answer
6k views

What is transaction replay and replay protection?

With everyone and their dog making new blockchains forked from the bitcoin blockchain, there is a lot of talk about replay protection. What is a transaction replay? What does replay protection do?
4
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1answer
470 views

How frequent are side-chain reorganizations of various lengths?

I'm wondering if anyone has collected statistics on how often reorganizations of side-chains with length 1 happen in comparison with lengths of 2, 3, or more. Related: What is the longest chain ...
13
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6answers
1k views

What keeps a dominant Bitcoin client vendor with the majority of the market share from unilaterally changing the protocol?

I've been asking this in the comments, but I'll be more direct. If a third-party Bitcoin client, say "iBitcoin" (for example), becomes the dominant client by acquiring most of the market share, what ...
7
votes
1answer
297 views

Could bitcoin “survive” a definitive hard fork, spawning a new currency?

What happens if two different groups have a definitive disagreement about the evolution of the bitcoin protocol? I have read is several places that the "majority" somehow would win, but is this really ...
3
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2answers
3k views

How does a double spend get resolved when two miners find conflicting blocks at the same time?

I was trying to learn about Bitcoin and its flow. Actually, I was stuck how the control flows in solving the double spend. For eg. if Ta and Tb are a double spend of the same transaction with ...
1
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2answers
328 views

Bitcoind confirmations during fork

I'm using bitcoind's JSONRPC interface to get transaction information for my wallet, specifically, I'm running a little script every time a block gets broadcast (using -blocknotify) which calls the ...
16
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3answers
481 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 ...
8
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2answers
745 views

Can the blockchain be outpaced by a chain of low-difficulty blocks?

Let's say someone creates a blockchain fork starting from the genesis block, when the difficulty was absurdly low compared to today; then he starts mining new blocks from there up to the current block ...
3
votes
2answers
221 views

How do I know I can trust the head of the blockchain

I'm trying to understand how the mining process works. Specifically, my understanding is the local miner works on blocks and add them to their local blockchain if they succeed. It may turn out that ...
3
votes
2answers
259 views

Detecting fork using bitcoind

What's the most efficient way to detect a fork in the blockchain? My app polls for changes to user deposit addresses on each new block. Deposits are credited to user accounts with a record in a ...
2
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1answer
517 views

Is the Bitcoin protocol secure if two parts of the network have no connection?

I'm trying to understand the Bitcoin protocol, and I have a security scenario. Let's assume that today between the internet connection between Europe and America is lost. John is in Europe John ...
0
votes
1answer
164 views

Bitcoin ABC, When Fed Bitcoin Core Chain Syncs to Aug 1 6:23AM 2017, Then Freezes

I've installed Bitcoin ABC, set bitcoin.conf to point at a copy of my directory from Bitcoin Core, and let it sync with the network. All was well until it froze at the fork (Aug 1, 2017, 6:23AM). ...
6
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2answers
2k views

What happens to extinct blockchains, and transactions inside of them?

While understanding the concept of block chain and proof of work, few things are confusing me. Miners always consider the longest chain(by difficulty) and work on expanding it. Now, lets say two ...
2
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1answer
806 views

Why not decrease the difficulty to increase capacity?

There is a persistent debate in Bitcoin about increasing the capacity. The popular idea seems to be to increase the blocksize from its current 1MB to push through more transactions per block. But ...
16
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5answers
10k views

Has a hard fork ever occurred?

BIP 50 describes the 2013 event in which a block chain fork persisted for several hours. Its first paragraph reads: A block that had a larger number of total transaction inputs than previously seen ...
21
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4answers
1k views

How often forks occur?

How often do forks occur in the block chain? I'm interested in the small, one block forks that happen when two miners create a block at the similar time.
7
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2answers
1k views

How to detect a fork with bitcoin-cli?

I'm keeping a simple log of blocks, and storing them in an array. When a new block arrives, I add it to the array. Let's say this is my block chain array: E <- tip D C B A Now, say a new ...
5
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3answers
3k views

Getting orphaned Blocks from the Blockchain

I'm very interested in doing some analysis of orphaned blocks, but to do so I'd have to have a good way of accessing them. Blockchain.info seems like a good place to start but I don't want to abuse ...
3
votes
1answer
417 views

Do new SIGHASH types need a hard fork or a soft fork?

There have been a few new sighash types proposed. SIGHASH_NORMALIZED : Use a 'normalized' TXID in the inputs when serializing for signing. This normalized transaction id is calculated by removing the ...
8
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2answers
460 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 ...
7
votes
2answers
521 views

What block numbers & hashes were discarded by the March 2013 blockchain fork?

When exactly (GMT) were these blocks mined?
1
vote
1answer
271 views

Segregated witness soft fork: how is the funding Tx made “ANYONECANSPEND”

Reading the BIP: https://github.com/bitcoin/bips/blob/master/bip-0142.mediawiki I see that the scriptPubKey in a transaction that funds a segwit redemption is the same as a normal P2PKH but merely ...
7
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2answers
3k views

Does my bitcoin multiply with every fork?

Simply put, does your current bitcoin (pre-fork) multiply with every fork that bitcoin may experience? For example if I have one bitcoin stored in a cold wallet for the next century and Bitcoin ...
4
votes
1answer
317 views

What client to use for an alternative special purpose blockchain?

Lets say one wanted to create a blockchain for the purposes of providing a scalable back-end for accounting for the trade of some arbitrary unit between people. It would not be a tradeable currency. ...
3
votes
1answer
321 views

How bitcoin nodes update UTXO set when their latests blocks are replaced?

Let's say bitcoin node has 100 blocks. Then he recieve another two blocks. Now it have 102 blocks. But now he recieve block 103. And this block is from another chain and our node have to remove blocks ...
3
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2answers
1k views

Is there actual consensus on the blockchain's tip or only until the next block?

Using this scenario https://bitcoin.stackexchange.com/a/40435 Let's say we have two competing blockchain tips: They both start from Block A as a parent, but then there are two different blocks ...
1
vote
1answer
106 views

Height mismatch between bitcoin-qt and bitcoin explorers

I am running bitcoin-qt on the testnet. The count of the last block is 787794 which is way ahead of what I see on blockchain explorers such as https://test.webbtc.com/, which shows the last block as ...
0
votes
4answers
233 views

What would happen if two miners were mining two blocks with two different set of transactions?

If two miners picked from the mempool two different sets of transactions, that were not dependent on each other. Then could both miners, mine both blocks and not create a fork? So miner 1 finishes ...
7
votes
2answers
341 views

In overview, what is “Bitcoin Cash” and the hard fork on August 1st 2017?

In overview, what is Bitcoin Cash? How is it different from legacy bitcoin? What is the blockchain hard fork which was supposed to happen on August 1st, 2017? Who benefits from the fork? Who is ...
6
votes
2answers
1k views

after hard fork won't every new transaction go on both chains?

I don't understand why I'm reading that after a hard fork, the existing transactions would be on both chains but the new transactions will only be on one or the other (resulting in 2 different chains, ...
5
votes
2answers
835 views

Transaction fees when a block chain is discarded

I'm a bit new to the bitcoin system, so I apologize if this is a "noob" question. A user attempts to take all the unverified transactions it knows about and aggregate them in a chain block. The same ...
5
votes
1answer
1k views

How does Bitcoin Gold implement replay protection?

The creators of Bitcoin Gold claim that they have implemented full replay protection. How does this replay protection work?
4
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2answers
225 views

Does a 2009 node sync the whole bitcoin blockchain

So does a 2009 node sync the whole bitcoin blockchain and does the temporary split of 2013 have any impact on that?
3
votes
1answer
288 views

Is it likely that side-chain support will be added to Bitcoin?

Is it likely that side-chain support will be added to Bitcoin? As I understand it, side-chain support will require a hard fork to Bitcoin to support this functionality: "moving" BTC to external ...
2
votes
1answer
963 views

Retrieve BCC/BCH but now have 0. Was i Hacked?

hey guys i followed an instruction from reddit and exodus chat and both had similar instructions to retieve Bitcoin Cash. I followed the instructions and it seemed like i received the coins though it ...