Questions tagged [blockchain-fork]

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

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What is a soft fork? What is a hard fork? What are their differences?

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?
Dr.Haribo's user avatar
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56 votes
2 answers
13k 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 ...
Stephen Gornick's user avatar
50 votes
2 answers
25k 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, ...
Emre K.'s user avatar
  • 3,188
12 votes
1 answer
5k 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, ...
morsecoder's user avatar
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23 votes
2 answers
4k 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?
kermit's user avatar
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25 votes
1 answer
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?
Dr.Haribo's user avatar
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20 votes
3 answers
2k 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 ...
CQM's user avatar
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15 votes
1 answer
8k 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.
Josh Cincinnati's user avatar
6 votes
2 answers
3k 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 ...
Haddar Macdasi's user avatar
45 votes
1 answer
14k 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?
Murch's user avatar
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13 votes
3 answers
14k 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 ...
Kitchen's user avatar
  • 133
11 votes
2 answers
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?
user189's user avatar
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5 votes
1 answer
607 views

How often does temporary fork occur and how long does it last?

I was wondering, how often does temporary forks occur? They appear when there are two different blocks mined based on the same previous block (parent block), but what are chances for that? And if fork ...
ddavi031's user avatar
  • 469
18 votes
1 answer
7k 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?
Dr.Haribo's user avatar
  • 8,439
10 votes
3 answers
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 ...
Brian Armstrong's user avatar
9 votes
2 answers
975 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 ...
Massimo's user avatar
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8 votes
3 answers
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. ...
DottoreM's user avatar
  • 205
7 votes
1 answer
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 ...
Mars Robertson's user avatar
6 votes
2 answers
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 ...
Avikarsha Mandal's user avatar
5 votes
1 answer
554 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 ...
Brian Armstrong's user avatar
4 votes
2 answers
428 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?
Bram's user avatar
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3 votes
1 answer
616 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 ...
fobus's user avatar
  • 147
16 votes
3 answers
527 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 ...
eMansipater's user avatar
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14 votes
6 answers
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 ...
Manish's user avatar
  • 2,022
7 votes
1 answer
304 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 ...
madjophur's user avatar
3 votes
2 answers
275 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 ...
mprivat's user avatar
  • 155
3 votes
1 answer
563 views

Will a hard fork be required to change timestamp fields?

In the protocol there are multiple timestamp fields with varying lengths. For example a 4 byte unix timestamp would overflow in the year 2106. Will a hard fork be needed to deal with this issue in the ...
Chiru's user avatar
  • 151
3 votes
2 answers
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 ...
Laxmi Kadariya's user avatar
3 votes
2 answers
292 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 ...
Aaron's user avatar
  • 31
2 votes
2 answers
978 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 ...
abelenky's user avatar
  • 1,344
1 vote
4 answers
631 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 ...
Kyle Graham's user avatar
1 vote
2 answers
361 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 ...
mpr's user avatar
  • 153
0 votes
1 answer
202 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). ...
Diagon's user avatar
  • 115
22 votes
4 answers
2k 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.
ThePiachu's user avatar
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17 votes
5 answers
11k 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 ...
Rich Apodaca's user avatar
  • 2,351
8 votes
2 answers
2k 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 ...
inersha's user avatar
  • 3,063
8 votes
2 answers
482 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 ...
Computerish's user avatar
7 votes
2 answers
391 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 ...
Jim DeLaHunt's user avatar
7 votes
2 answers
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 ...
Josh's user avatar
  • 630
7 votes
2 answers
558 views

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

When exactly (GMT) were these blocks mined?
ripper234's user avatar
  • 26.6k
6 votes
2 answers
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, ...
RentFree's user avatar
  • 2,539
5 votes
1 answer
2k 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?
Ava Chow's user avatar
  • 70.4k
5 votes
3 answers
1k 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 ...
abelenky's user avatar
  • 1,344
5 votes
3 answers
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 ...
cdecker's user avatar
  • 9,438
5 votes
2 answers
984 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 ...
Gil Moshayof's user avatar
4 votes
1 answer
419 views

What are the last common blocks of Bitcoin and its hard forks (Bitcoin Cash, Bitcoin SV etc.)?

What are the last common blocks of Bitcoin and its most popular hard forks like Bitcoin Cash, Bitcoin SV, Bitcoin Gold, Bitcoin Diamond etc.?
dassd's user avatar
  • 1,059
4 votes
3 answers
530 views

Would it be possible to create a soft-fork for reducing miner reward?

Context: There is a bet going on r/bitcoin about the possibility of doing a user activated soft fork for reducing current miner reward to 0.25 BTC. One of the users says the bet had two points: the ...
My Quid Pro Quo's user avatar
4 votes
1 answer
203 views

How is network conflict avoided between chains?

I have a question which may appear obvious but hopefully it’s not. How do different Distributed Ledger Technologies (DLTs) and cryptocurrencies avoid network conflict? I understand the distributed ...
LeosSire's user avatar
4 votes
1 answer
387 views

When does a blockchain fork resolution happen?

I understand that forks are resolved by largest proof-of-work etc. but when do the miners decide to resolve a fork? Is it a question of network consensus or does each individual miner resolve at their ...
Larrrrrrrrrry's user avatar
4 votes
1 answer
336 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. ...
barrymac's user avatar
  • 1,605