The National Institute of Standards and Technology from the United States Department of Commerce has stated in a high level overview of blockchain technology and cryptocurrencies that “Bitcoin Cash is the original blockchain.” They say:
“In July 2017, approximately 80 to 90 percent of the Bitcoin computing power voted to incorporate Segregated Witness (SegWit, where transactions are split into two segments: transactional data, and signature data), which made it possible to reduce the amount of data being verified in each block.
Signature data can account for up to 65 percent of a transaction block, so a change in how signatures are implemented could be useful.
When SegWit was activated, it caused a hard fork, and all the mining nodes and users who did not want to change started calling the original Bitcoin blockchain Bitcoin Cash…
Technically, Bitcoin is a fork and Bitcoin Cash is the original blockchain. When the hard fork occurred, people had access to the same amount of coins on Bitcoin and Bitcoin Cash.”
This is an interesting interpretation of events and is worthy to bear in mind they say “this document attempts to bring a high-level understanding of the technology.” That is, they are focusing on concepts, rather than intricate detail.
Technically, as far as correctness goes, they are right. Although some developers use the soft-fork and hard-fork concept, as far as the network is concerned regarding validation, processing, and so on, there is no such thing as a soft-fork. Nodes that do not upgrade just stop validating properly and become less secure.
For miners, all upgrades are a hard-fork. Any miner that did not upgrade to segregated witnesses (segwit) would have forked off and would have created their own blockchain, as has happened a number of times during “softfork” upgrades when a mining node accidentally does not upgrade.
In July 2017, segwit reached its activation threshold, as we reported at the time. That was followed by a miners hard-fork in August, which was backwards compatible with non-mining nodes.
Bitcoin, therefore, is a fork, with the network considerably changing in a fundamental level after segwit’s activation, but is Bitcoin Cash a fork at a high level?
The National Institute of Standards and Technology says it is not and that BCH is “the original blockchain.” At a high level, that is probably correct.
It did change difficulty to keep the original blockchain running and it did increase the blocksize, but those are not such fundamental changes as to call it a completely different system like bitcoin is with its planned settlement layers.
Since the beginning bitcoin has had a method to increase the blocksize, with the cap initially being 250kb, raised to 500k, 750kb, then 1MB.
At 1MB miners refused to raise it further, despite Nakamoto clearly stating the network should keep scaling by increasing the blocksize.
Miners, thus, instead forked off to a completely different system, which is nothing like what is stated in the whitepaper, and thus shouldn’t really even have the name of bitcoin. While Bitcoin Cash kept the original chain running, making it the real bitcoin.