I have read that a story in TruStory once falsified can still be challenged and changed the status in future. So for me, I understood this as the status of a story is editable even after completion of its token payout and the transaction is verified/confirmed on TruStory blockchain. So how does this work with immutability aspect of data on a blockchain? Is this a use case which can be tecnically implemented on a blockchain?
A blockchain is immutable, as in previous transactions cannot be altered. It doesn’t necessarily mean data stored on a chain is immutable. It depends on how it’s is stored. Generally, data can be altered by transactions. In the case of TruStory, we are storing data in an immutable decentralized datastore on-chain. Immutable in this case means that the datastore is append only – once you write something to it, it’ll always be accessible. A future transaction can still modify this data, but the record of that modification will always be there. You can always go back and read data from a block height in the past to get the data at that point in time. In TruStory, story data can be modified by transactions, but the history of those modifications is immutable, and will always be accessible.
@shane: A blockchain is like a ledger of accounts where each entry is recorded and all the participants (account holders) have a copy of the ledger. It is a collective responsibility of all the participants to maintain the ledger and its identical status. And that is why maintaining a ledger( the decentralised database) is an expensive process.
Do you have an idea of the expensiveness of this process?
@shane Thanks for the clarification! Steemit posts were not editable initially after a specific time and I was thinking it had something to do with the blockchain! Like anything goes to blockchain stays their permanently without option to modify:) But No! That was their implementation and they have added the edit feature now.
Let me try to clarify with an example.
It is kind of like saying if you have a balance of 2 bitcoin, then your balance is forever 2 bitcoin because the blockchain is immutable. If this were true, then you wouldn’t ever be able to send or receive more Bitcoin.
Luckily, we can send Bitcoin to other people.
What immutability in the blockchain refers to is that data in very old blocks never change. New blocks are added and you can make new transactions which can say “Alice sent 1 bitcoin to Bob”. It’s an append-only ledger. So now you can look at the history of transactions and know older blocks haven’t been changed or tampered with.
Hope that helps!