As the first cryptocurrency in existence and the one with the longest history, there has been not one Bitcoin fork but a few. There had been some forks related to technical questions such as block size and target difficulty. Others have been due to personality among developers. Either way, there are more than a dozen blockchain protocols out there that call the Bitcoin genesis block their origin.
What's a Bitcoin fork?
Basically, a fork can be interpreted as an update to the Blockchain. Unique to the decentralized world, these updates cannot be imposed on the community, it has to be agreed by the miners for it to work. This leads to two possible outcomes for when a change is proposed, a soft fork or a hard fork.
The main characteristic of a soft Bitcoin fork is that it is backwards compatible. Effectively, this means that miners are able to choose if they want to join or not and the network's integrity remains unaffected. Of course, there is a cost. The new features brought by the update to the nods using it won't be there for those not using it. There can be some costs to this since traffic can go to those supporting the update in detriment of those that not. Either way, the network remains whole.
Now a hard fork is completely different. This time an update is not compatible which means that after pushing for it the network is split between those going on the direction and the other going a different way. There is no way of joining the chains once broken, so the fork is permanent. This is dangerous since the mining power of the network is divided and the smaller section is more vulnerable to attacks. Interestingly though, if you have 200 crypto coins in the network before the change, after it you have the same amount of coins in the original chain and two-hundred in the new one. This is because both originated from the same network and shared the same data prior to the split.
Litecoin (LTC)
On October seventh of 2011, the Litecoin client was released on GitHub. It was developed by Charli Lee a former Google employee and director at Coin Base. It is a fork of the Bitcoin Core client with the main differences being The processing time is two and a half minutes, It uses Scrypt as its hash function, and the total supply is eighty-four million coins.
The hash algorithm Scrypt is more difficult to process than SHA-256. This means that the specialized hardware made to made Litecoin such as ASICs is more complicated to build. This added expense makes mining pools for the Litecoin network are more concentrated.
In 2017 support for Litecoin in the Lighting Network was integrated. It is also notable that Litecoin was the first major cryptocurrency to adopt Segregated Witness (SehWit) also in 2017. Litecoin is the 7th ranked coin by market cap.
For a complete guide of the best wallet to store LTC read this link.
Bitcoin XT (BXT)
This was an aborted attempt. It is notable as an almost successful attempt to increase capacity in each block. It would achieve this by doubling the size of blocks every two to its target of 8 mega bites. The proposed fork was meant to start in 2014 if 75% of the network adopted the update. The target size was not reached and the project fell apart.
To understand better the debate read a full explanation in this article.
Bitcoin Cash (BCH)
The main split in of BTC happened on August the first in 2017, on Block number 478558. The origin of Bitcoin Cash came as a conclusion of the block size debate. As we saw with Bitcoin XT there were past attempts to change this feature, others include Bitcoin Classic and Bitcoin Unlimited.
In July of 2017, the debate over the blocksize reached an impasse. It was around the time the SegWit update was being considered and members of the Bitcoin community didn't feel it was enough. Among the most vocal detractors was Roger Ver, an early Bitcoin investor. Their argument was that keeping the current limit favoured the use of Bitcoin as an investment vehicle and not a medium of exchange.
The team desired to increase the capacity of the blocks, in an attempt to boost transactions across the network and that way push cryptocurrency adoption. This is the origin of the name Bitcoin Cash, as finally user would buy and sell with the crypto and not just hold it.
There aren't other important differences between BTC ad BCH. The two have a maximum amount of twenty-one million both use PoW, and SHA-156. The major difference is that the blocks in BCH are 8 mg and the client of the network doesn't use Segwit.
Briefly, in 2018 due again to differences in the block size BCH has a hard for, and the new chain was named Bitcoin Satoshi Vision with a capacity of 128 megabytes. It was transformed into Bitcoin ABC and increased the block size to 32 megabytes.
Bitcoin Gold (BTG)
Bitcoin Gold is a hard fork of BTC that happened on the twenty-fourth of October 2017. On block number 491407. The team behind the fork cited concerns over the centralization of the Bitcoin network due to the proliferation of ASIC rigs for mining. This means only people with enough money are able to mine BTC competitively leaving a large segment of the world from participating. We end with half of the network concentrated in three major pools.
To address the issue, Bitcoin Gold modified the hash algorithm on BTG. The new algorithm called Equihash is not compatible with ASICs it works only for GPUs. Despite this change, last year the BTG was targeted on a 51% attack and had to divide to preserve the network.
Bitcoin Private (BTCP)
As an example of another debate in the Bitcoin community, privacy, there has been a push to make Bitcoin more surveillance resistant. This hard fork happened in February twenty-eight in 2018 on block number 511346. The coin resulted from a union of ZClassic and Bitcoin. The first one being a fork itself of ZCash and crypto-focused on privacy.
As with the case of Bitcoin Gold, BTCP is ASIC incompatible as it also uses Equilash. This again in an attempt to reduce centralization. To improve privacy it offers users the ability to generate public or private addresses. This is possible due to the implementation of Zero-Knowledge Succinct Non-Interactive Argument of Knowledge (zk-SNARKs).
We made a quick summary of the major Bitcoin hard forks that split the network. These are by no means all there is. There are others such as Bitcoin Dimond (BTG), Bitcoin ATOM (BCA), Bitcoin BitVote (BTV), Bitcoin Stash (BSH), and many more. Some are still around and others ceased to exist.
This is a necessary product of the decentralized nature of Bitcoin. The moment a dispute becomes unsolvable among the mining community and part of the network can split. Although the divisions by themselves are not a problem, the resulting protocols tend to have fewer miners. These are very concentrated blockchains and are easily attacked killing many of the projects.
