Blockchain may be 100 times as large as Google’s Servers
So the reason that blockchain is more secure, as you mentioned, is that there is this ledger which is continuously updated, and each transaction that happens on the ledger is added into a block, which is connected to every other block going back to the history, to the beginning of the blockchain.
What that means in practice is, if you wanted to alter a transaction, to change the record of what has occurred, you wouldn’t just have to attack one computer, you’d have to attack millions of computers simultaneously. And you wouldn’t just have to rewrite one transaction, you’d have to rewrite every transaction all the way back to the beginning of blockchain. And you wouldn’t have all the time in the world to do it; you would have to complete this massive attack in a matter of a few minutes. And you’re not just fighting one computer system, you’re fighting a whole bunch.
It’s estimated that the combined computing power of the biggest blockchain, which is the bitcoin blockchain, is 10 to 100 times as large as all of Google’s server farms. Which makes basically means it’s about 100 times more difficult to hack than one of the largest and most secure systems in the world.
So if you’re talking about securing and storing sensitive financial information, or information about individuals such as their health records or how they voted, it’s really important that those systems not be vulnerable to attack, and with blockchain we’ve found by far the best solution to securing that information.
http://business.financialpost.com/midas-letter/podcast-blockchain-revolution-co-author-alex-tapscott-on-brexit-opportunities











