How is Blockchain secure? And how the blocks will be functioning in a chain?
Already it is a known fact that the blocks will be linked to a chain. Upon the hash of the previous block, this will be done by each of the block building. If at all, the hash of any block is changed in a Blockchain technology. The consecutive blocks will be no longer recognized as a valid element. In turn, this will render the entire chain as useless, thus not validating any kind of tampering with any block. Blockchain provides this as one of the security measures. The disturber will have to rework the hashes of the entire following blockchain, in case if any tampering has to be made.
Besides this, the Blockchain will be using a “Proof of Work” concept for enhancing the security. It is to be noted that a “Proof of Work” can be equated to the processing time taken by means of a computer. Necessarily this will be slowing down the creation of a new block in a Blockchain. For instance, in a Bitcoin Blockchain, this will be taking around 10 minutes for creating a new block. Therefore, for altering an absolute Blockchain, an individual had to invest 10 minutes upon each block of a Blockchain, thus making the process nearly impossible.
However, these measures do not guarantee that the value of a block cannot be changed. Hence, there will be one ultimate security measure, that the Blockchain uses. As aforesaid before, the Blockchains will be using a “distributed ledger, even called as a Peer-to-Peer network. That means, even if one handles to alter one particular copy of a Blockchain, by means of adding a defected block, the altered block will yet not going to be accepted into the system.
The reason for this is simply because the altered block will not be matching with the copies that others having in a system and therefore will be discarded. If a block is to be accepted into the system, then it has to pass a consensus. That means it has to be validated by more than 50 percent of the network. So this will be making the alteration of any Blockchain almost impossible.