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?
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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 ...
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?
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, ...
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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?
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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.
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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?
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 ...
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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 ...
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?
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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 ...
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3answers
6k views

How is a hard fork resolved?

In March 2013 there was a fork following the v0.8 release. The issue was resolved rather efficiently, as explained in the post-mortem report. However in this process there were winners and losers: the ...
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 ...
13
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2answers
708 views

What should I do about the March 12th 2013 blockchain fork?

Reddit/r/bitcoin is flooding with news that the Bitcoin blockchain has forked, in that versions 0.7 and 0.8 are accepting different blockchains. What does this mean for the users?
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3answers
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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 ...
11
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1answer
5k views

Preparing for Bitcoin Gold

I have been holding a small amount of bitcoins on Coinbase and am deciding to move it to wallet. I wanted to be prepared for the Bitcoin Gold fork coming up in October and was curious about the best ...
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.
10
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1answer
7k views

What happens to coins after Bitcoin Cash fork?

I'm new to Bitcoin and I read that there is a fork going to happen on Aug 1st to create Bitcoin Cash (BCC). From https://ethereumprice.org/ethereum-classic-and-bitcoin-cash/?a=1&b=https://...
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 ...
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, ...
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?
10
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3answers
938 views

What should I do if my friend runs a Bitcoin business but doesn't understand how it works?

My friend doesn't listen to his head of engineering and doesn't fully understand how decentralized consensus based systems like Bitcoin really work. He seems to think a new untested/buggy ...
10
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1answer
2k views

The incident with 92 billion bitcoins

There is a documented case from 2010 when a block with 92 billion bitcoins was discovered. The bug was found and software was patched within 5 hours and everyone had to "hit the load button" to an ...
9
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1answer
679 views

Strange transaction (block 71036)

What happened to this transaction? Can someone explain it? http://blockexplorer.com/t/9eHTFRi3Qq
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 ...
8
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3answers
723 views

Testing blockchain forks

I want to test if a service can manage a blockchain fork. However there is no way to get bitcoind to create test forks under the regtest mode. I've tried modifying it to generate blocks with arbitrary ...
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 ...
8
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1answer
1k views

At what point does a hard fork occur?

with the whole debate and concern over a looming Bitcoin hard fork I would like to ask at what point has the hard fork occurred? Is there a specific moment when developers decide to implement BTC/BTU ...
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. ...
8
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1answer
1k views

How was the blockchain's “hard fork” automatically resolved?

As a result of an "official" change in back-end databases from BDB in v0.7 to LevelDB in v0.8, in addition to an increase (by some mining pools) to a higher block size limit, there was recent "hard ...
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2answers
249 views

Given the recent <0.8 bug, when can we safely have larger block sizes?

Given the <0.8 bug and subsequent fork happened because of a particularly large block, does this mean that large blocks can not be used until the large majority of the community switches to 0.8? ...
8
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3answers
328 views

Forks to be aware of other than Bitcoin Cash and Bitcoin Gold?

I have now taken care of the Bitcoin Cash and Bitcoin Gold that I was given "for free" when the hard forks took place, and sent them to other wallets. Before getting rid of [*] my old Electrum ...
8
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3answers
616 views

Valid fork in regtest - Change blockchain via RPC?

I've created a regtest network consisting of 2 nodes - node0 & node1. I'd like to have a fork on the common blockchain and seemingly achieved it by doing so: nodes start node0 adds node1 via ...
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 ...
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 ...
7
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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 ...
7
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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 ...
7
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2answers
492 views

How does a Bitcoin client efficiently change forks?

Occasionally, a Bitcoin client will come across a fork of blocks that is longer than the chain it is currently on. Depending on how often orphaned blocks occur, this could be quite often. When this ...
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 ...
7
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2answers
521 views

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

When exactly (GMT) were these blocks mined?
6
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3answers
683 views

Why doesn't bitcoin place additional constraints on competing block chain forks, other than length of chain? (e.g., time and confirmation count)

In Bitcoin's proof-of-work system, consensus on which chain of blocks should be considered the "true" block chain is based only(?) on which chain is longer. Accordingly, to quote a nicely written ...
6
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1answer
1k views

Who wins the race for multiple valid blocks mined at the same time?

From my understanding, a SHA256 hash is generated by a miner and if the hash is less than a specific value, it is passed to its peers. That said, It's possible for multiple hashes to be created at ...
6
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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, ...
6
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2answers
736 views

Have bitcoin developers applied the solution for selfish miner attack?

The Majority is not enough paper proposed an academic and somehow practical attack to Bitcoin mining system based on creating hidden forks. The paper claims that if miners work on whichever fork they ...
6
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2answers
239 views

If there is a block-size hard fork, will the old chain have an advantage?

On his blog, Mircea Popescu claims the old chain will have an advantage: The situation here is aggravated by the fact that the fork proposed is not simply nondeterministic behaviour, and so the ...
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 ...
6
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2answers
214 views

Who makes the decision about blocksize?

I have been running a full node for little less than a year and I am following the discussion around blocksize increase. I am for it. Who actually can make a decision whether the blocksize increase ...
6
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1answer
138 views

What's the formula giving the % of succesfully maliciously messing the blockchain?

With the recent (early 2014) GHash.io concerns about that particular mining pool getting too big, many people have talk about what a powerful miner could do if it wanted to "harm" bitcoin or double-...
6
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2answers
123 views

When will a block not be forwarded?

I'm currently trying to detect blockchain forks and I noticed that even when dumping all blocks I get to a separate file I seem to miss a few. Specifically I'm looking for the blocks marked as ...
5
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3answers
972 views

Is there a list of Bitcoin Forks?

I have some Bitcoin from before the Bitcoin Cash fork, and am pleasantly surprised to learn it has some significant value. I believe there have been a number of other forks as well. But I don't have ...

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