In a Blockchain, how difficult is it to modify the third to last block?

0 votes
Let's say my Blockchain has N no. of blocks. My question is - how diffcult is to edit (N-2)th block on the PoW Blockchain?
Apr 20, 2018 in Blockchain by Perry
• 17,020 points
65 views

1 answer to this question.

0 votes

Technically, it's not difficult at all, all you need to do is recalculate all of the entities after the one that was modified. This is straightforward and inexpensive. 

Although, that will give you five new hashes, so everybody immediatelly notices that someone has manipulated the Blockchain. that is one of the fundamental features of PoW Blockchain.

answered Apr 20, 2018 by Christine
• 15,790 points

Related Questions In Blockchain

+1 vote
1 answer
+1 vote
1 answer

Is it possible to store blockchain in a sql or no-sql database?

Currently, following are the options to store ...READ MORE

answered Apr 20, 2018 in Blockchain by Perry
• 17,020 points

edited Aug 9, 2018 by Omkar 61 views
0 votes
1 answer

How can I take the required info and send it to a div in the html page?

window.onload=function(){ var anima = document.getElementById("crypto"); var ret = document.getElementById("btn"); ret.addEventListener("click",function(){ var ...READ MORE

answered Sep 6, 2018 in Blockchain by digger
• 27,640 points
34 views
0 votes
1 answer

Truffle tests not running after truffle init

This was a bug. They've fixed it. ...READ MORE

answered Sep 11, 2018 in Blockchain by Christine
• 15,790 points
138 views
0 votes
1 answer
+1 vote
1 answer

What problem does pow(proof of work) solves in blockchain?

Proof of Work: When a miner gets a ...READ MORE

answered Aug 6, 2018 in Blockchain by digger
• 27,640 points
56 views
+1 vote
1 answer

I would like to create a blockchain network which will stay at the same level of complexity, is it possible?

You can very easily create a cryptocurrency having a ...READ MORE

answered Apr 4, 2018 in Blockchain by Christine
• 15,790 points
48 views
0 votes
1 answer

How to make sure transactions take no fee in a private Ethereum blockchain?

In a private ethereum network you have ...READ MORE

answered Mar 26, 2018 in Blockchain by Christine
• 15,790 points

edited Mar 26, 2018 by Christine 93 views