> Ellison testified how colleagues at Alameda set up accounts on the Chinese exchange tied to the identities of Thai prostitutes, hoping they could somehow use those accounts to siphon the money away from the frozen account.
Suppose Company X buys 100k in hashing power and signs everything accordingly so it all looks fine. How do you know they didn’t instead buy 200k and run two blockchains side by side until they need to pick one months later?
Alternatively, they instead buy 1M in hashing power so they can spend 1 day making a believable 10 days worth of history on 100k hashing power blockchain.
Now you can argue publishing a blockchain makes it immutable, but so does publishing anything else. Don’t want people to see the data? Publish hashes of your database backups.
Set N = 0 dollars of hash power and it becomes really obvious that the person running the network can just arbitrarily create any blockchain they want at any time for ~zero cost. It therefore clearly isn’t an “immutable system of record” because they can change it.
But let’s flip it around what specific benefit are you proposing and how exactly does cryptography enable it differently than a Bank.
Also the "most trivial case" you're proposing here is a strawman. You demonstrate that your trivial case wouldn't work and everyone who does this knows that it wouldn't work so that's not how it works. Genarally these chains submit a transaction proof to some base chain so they can't go back later and rewrite history unless they could also rewrite history on that base chain.
Here's a source if you want to read up about how these things actually work https://wiki.polygon.technology/docs/cdk/
However, I was specifically responded to someone who seems to think blockchain = immutable system of record and I was pointing out that private blockchains don’t provide that because the mechanism public PoW chains uses to get immutability isn’t applicable.
I realize there are a lot more than just 1 way people are proposing private blockchains and most of them involve publishing something, but as long as we can agree the blockchain bit is pointless then discussing them is a waste of time.
So, it would be noticeable if every prior node and all its contents were published and people are validating the integrity of those prior nodes. Which is true of literally any public ledger.
The specifics of what get published can make things more convenient as there’s more locations you can send hashes of logs than the full logs, but publishing hashes alone doesn’t do anything without those logs also being public.
Banks carry insurance.
Bitcoin and other public PoW blockchains are decentralized.
> Banks carry insurance.
And???
On a private chain you can easily change the data. Remove the hashing fig leaf and it’s even easier.
On a public one it’s the public nature that prevents changes after publication. So no, being a blockchain doesn’t prevent changes whatsoever. Having a public ledger does.