Quote from: Maveth13 on July 05, 2018, 01:40:49 PM

Technically, blockchains are not unhackable, but it's extremely hard and expensive to pull off. An example are Sybil attacks, and again, this is highly improbable. Another example is an attack through ISPs, since nodes are relatively centralized.

For the most part, reported hacks happen in exchanges and wallets, not in the blockchain itself.

i think you are confusing "hack" with "attack" these are two different things.
a hack is called to something like your computer getting hacked and you lose sensitive information such as your passwords, private keys, money,...
an attack like the ones you listed here such as Sybil attack, the results of an attack are not severe as a hack and most of them don't even end up in losing anything.

as a simple example, DDoS "Attack" against a website only puts it out of service for a short time. but a website "Hack" means you change the things on that site, steal something like user information,...