Use Cases of Blockchain
That's a lot of data!
Why do data and blockchain get along so well? -
This is because one of the benefits of having multiple nodes or people with the same record set is that they all check new data and agree to what is accurate and what is not. This leads to better data accuaracy and higher levels of data integrity because to delete the data a hacker would have to delete several records all in different locations making a coordinated strike difficult.
The dreaded 51% attack -
Blockchains have miners sometimes. Miners are people who put up there computer power to serve the blockchain. Tranlastion : use my computer as a processor and when we add a block (a record) to the blockchain (the distributed ledger) when 51% of us agree. A 51% attack is quite rare because it can only be succesful on a smaller blockchains. This is because they take a lot of coordination and finding exploits and larger blockchain are to resilient due to there being more miners.
The Attack Hash Rates ! -
To make things simple hash rate is like the amount of cryptographic power you need to mine blocks aka validate records. If a user could get 51% of that hashrate power to himself or a group they could essentially rewrite the record for their needs which could theoritically mean they could double spend cryptocurrency or spend it twice.
How it works ?