I just want to ask, can someone provide a wrong input in the Blockchain? What will happen if someone wants to input an error in the blockchain? What are the counter measures?
Hello, since you are asking about the Blockchain (and not the Bitcoin Blockchain application), I think it depends on why are you using this. I don' t think any mined blocked can be deleted, but you can always add another one in which the information is corrected. For instance, you have this new in the newspaper: it has been already published, so you can' t just modified it in the case that the newspaper is already printed, so the only way of making any needed correction is to add in the next publication an "erratum disclaimer".
The blockchain works the same way, from my perspective: you can always modify a previous block by just adding new information to the next if corrections are needed.
Anyway, this seems to be a preoccupation for some developers. Since 2016 the idea of developing a Blockchain in which data could be changed was in a company called Accenture designing a new Blockchain model with such characteristics. Of course, it was not very liked by the community, I'm afraid, for it kind of goes against the crypto spirit.
You can read more about that in here:
https://www.ft.com/content/f5cd6754-7e83-11e6-8e50-8ec15fb462f4Now, regarding crypto, I don't think that the editing mode should be allowed, for it is against the mere existence of the Satoshi' s Blockchain idea. But this is just my opinion. The Accenture guys have their own in here:
https://www.accenture.com/us-en/insight-perspectives-capital-markets-edit-blockchain-question