Some interesting post brings to me some ideas to the table. Lets discuss how to theorecally attack a BC and commit fraud on it (never done since the start in 2008).
- Shutting down the Internet.
- Or shutting down all the nodes running the BC.
The 51% Attack
Its a very large flaw in public BC like BTC. If a single entity had the majority of the hash rate then it could manipulate the public ledger. This would undermine confidence and create panic among participants, prevent transactions to be recorded, reverse transactions, prevent other miners to find blocks, etc. Its very costly attack because of the computation cost.
The Eclipse Attack.
Here we cripple a node in such a way that it can´t talk to other nodes in the BC. This reduces the % hashrate needed to launch a 51% Attack. Eg 3 nodes with 30%, 30%, and 40%. If the 40% node manages to cripple one of the other 2 then it can launch a 51%.
The only related successful attacks have been on the services running over this technlogy, like the DAO Attack happened in the Ethereum BC and hacked the Eth smart contract code, or the Mt Gox Bitcoin exhange.
Therefore the protocol is SAFE. Only thing to be compromised is the ecosystem built on top of it. But how about China holding more than 51% of the capacity.