Understanding SegWit2X & Replay Attacks
Segwit2X hard fork will occur in about a month.
This is the hard fork that most of the Bitcoin community is unenthusiastically waiting for.
So if you’ve been wondering what’s the big deal about it, let’s take a look at SegWit2X.
This is an attempt to address the scaling issues currently plaguing Bitcoin by increasing the size or more specifically, the weight of the blocks of the Bitcoin blockchain.
The reason this change can only be implemented as a hard fork is due to the fact that this change requires the legacy nodes to upgrade.
You can think of legacy nodes as the original nodes of the bitcoin blockchain that have never upgraded.
This means they follow the original protocols set in place when Bitcoin was first created.
SegWit2X would require these nodes to accept blocks that they otherwise would have rejected prior to the hard fork.
Because this change would ultimately increase what is being called the weight of a block, this in turn increases the workload for the nodes of the Bitcoin Network. It will also affect the miners.
(I’ll include links down below that go much more in depth on how exactly the nodes and miners will be effected so you can get a better idea of how this hard fork will change things.)
This may sound like a simple and logical move to help the network deal with the increase of transactions, but it’s important to note that like everything else involving Bitcoin things get technical and philosophical.
There is a very important issue with SegWit2X that I think everyone who uses Bitcoin needs to be aware of, and that is the threat of replay attacks.
If a hard fork occurs and neither the new or original blockchain implement protocols and protect against replay attacks, things can go south.
When a blockchain splits, the original blockchain or legacy blockchain and all of its past transactions are the same on the newly split blockchain. This is why we are able to receive an equal amount of the newly created coin if we were holding the original coin at the time of the split.
At the time of the split however, if there is no replay protection protocol implemented by either the legacy blockchain, or the new one, new transactions that occur on either chain could be copied and sent on the other chain. This would cause anyone sending BTC or the new hard forked coin to accidentally send both coins to a lucky recipient.
This also opens the door for malicious actors to receive both coins when the intention was to send only one.
Enter: Replay Protection- a protocol that ensures that new transactions are valid on one blockchain and not the other.
It’s true that either the original blockchain or the newly formed blockchain can implement this replay protection to prevent this type of double spending.
However it would be much easier for the new blockchain to implement this security. This is because the original Bitcoin blockchain network is so widely spread the likelihood that this security protocol would be implemented in time is very slim.
This can be quite confusing to understand so you can find links down below for additional articles and blog posts that go much more into detail on how exactly this hard fork will effect the blocks and how replay attacks happen and how they can be prevented.
Additional Reading/Sources:
Explaining SegWit2X Replay attacks
More on block size vs block weight
List of supporters for SegWit2X (includes exchanges and wallets)
Great job explaining everything Heidi
These forks are sort of out of control. Here was the picture I made of what CoinMarketCap is going to look like in 2018.
Love it!
daamn thats sick! .. do I see a steem fork there? shouls i be worried?
That looks like the original steem , not fork
We should all be worried. I put ShitConnect in the #3 spot and UET (Useless Ethereum Token) in the #8th spot. Yikes!!!!!!
This can already happen -- not via hard forks but by normal people forking the BTC code and establishing their own coins.
The scary thing about that-- even though said jokingly-- is that IT MIGHT JUST HAPPEN!
Yeah I made one like that too, only the first 100 coins are all bitcoin forks. lol
great graphic!
thats really made, kinda takes the shine off our precious bitcoin to! feel bad
Excellent description of the upcoming hard fork. Much appreciated.
Great post. Thanks for the valuable information.
Thanks for the overview of some of the mechanics involved there. I have been learning the mechanics of a few different blockchains recently in preparation for launching my own Steem Witness server - which I have just done.
I would be honored and greatly helped if you would consider voting for me as witness here at Steemit - My witness application post is here.
The more votes I get, the more time I can invest in helping improve Steemit. :)
Great info
Very detailed info about SegWit2X. My quetion is: how are the miners going to be affected, positive or negative?
Considering 85% of the hashpower on the network supports 2x, they obviously think it is in their interests.
thanks @heiditravels very helpful post for someone new like me in Bitcoin and cryptocurrency
Since when are twitter polls indicative of community support in one direction or another. In Bitcoin there are exactly 2 metrics that cannot be faked, and one is a centralized bolt-on. The first is obviously hashpower - which has been signalling overwhelming support for 2x.
Additionally, signatures made by BTC addresses containing funds (stakeholders) also cannot be faked. These poll results appear to be more or less in agreement with the hashpower.
It's absurd that anyone would take claims that 2X lacks community support seriously.
Great stuff as always, Heidi.
I looked at the list of supporters that you linked to and laughed when I saw the "LOL" response for SegWit2x. So great.
Andreas Antonopoulos basically seems to prefer Lightning network and off chain solutions saying that in engineering often times the simple way is the wrong way...