How is cryptographic hashing irreversible?

Hashing is quite complex, and it’s impossible to alter or reverse it. No one can take a public key and come up with a private key. Also, a single change in the input could lead to a completely different ID, so small changes aren’t a luxury in the system.

If someone wants to corrupt the network, he/she would have to alter every data stored on every node in the network. There could be millions and millions of people, where everyone has the same copy of the ledger. Accessing and hacking millions of computers is next to impossible and costly.

That’s why it’s one of the best blockchain features. As it’s too hard to bypass, you won’t have to worry about hackers taking all your digital assets from you.