Is blockchain really immutable?

Having read that #blockchain_is_immutable, would have surprised you to some extent that how is this actually possible or attainable??

Well to answer this, it is attainable. And all credit goes to cryptographic hashes and various consensus mechanisms used in blockchain, which makes blockchain immutable. The main advantage of hashing is that it cannot be reverse-engineered (One of the differences between hashing and encrypting). That’s the reason why it is so popular. The most popular hash function is SHA-256, i.e., Secure Hash Algorithm 256.

There’s an input that goes into the hash function with a checksum as the end-product. In the side image, we can see how ‘Blockchain is Disruptive’ goes as an input, after which hashing occurs, resulting in an encrypted output as a checksum.

Here in the below image, after hashing of a block, the checksum of it is an input to another block, which will generate a checksum as an output. Each iteration here will result in a different checksum every time. In a block, the transactional data is processed with the previous hash along with the Meta-Data and TX Data Hash, which altogether is hashed. That’s why the checksum generated at every block is always unique. This certainly explains?why blockchain is immutable?to some extent.

Now, if I say that blockchain still can be tampered with and Blockchain is not 100% immutable. Yes, nothing is 100% full proof, not even blockchain. So in the next article, I will be telling about some attacks that can risk blockchain.

to be continued...

References:

https://www.upgrad.com/blog/what-makes-a-blockchain-network-immutable/

https://dzone.com/articles/a-guide-to-blockchain-immutability-and-chief-chall