How secure is Bitcoin? How strong is the security of Blockchain? How immutable can it be?
The interesting thing about Bitcoin is since its inception, no one’s cracked it. Yet it’s completely in the open.
Blockchain, or Bitcoin, to be specific, survived not because it had not been attacked. Indeed, it had been attacked 24/7 since day one.
In order to understand how secure a blockchain could be, we shall look into the technical and system design part of it, namely Asymmetric Cryptography and Distributed System.
Once you have the basic idea of how things are being construct, you shall have more confident on the security part of it.
Blockchain is Military Grade Security
Bitcoin survived not because it had not been hacked. It is being hacked 24/7 since day 1, and it survives. This is not saying that it won’t be hacked in the future, such as the quantum computing possibilities certain parties are working with. The point is, if a system with its source code widely available to the public can survive for the past 9 years, it is needless to say how strong it is, by design.
Let’s use the centralized banking system software system to illustrate the scenario. Imagine a big bank’s computing system source code is made public. That is a major disaster. Theoretically, when people gain access to any system’s source code, the system is doomed. That was before the born of Bitcoin, or the first Blockchain.
Bitcoin is a collection of concepts and technologies that form the basis of a digital money ecosystem. ~ Andreas M. Antonopoulos, Mastering Bitcoin, 2015
The system is construct in such a way that there are some economics working in the background.
Distributed System
In a centralized system, the point of attack is obvious. You can’t attack effectively when you don’t have a clear target. In other words, in a distributed system’s environment, hackers can’t just hack a computer and consider job done.
They will have to hack every single node or computer in the network, almost at the same time, or in a very limited time frame, in order to make changes to the same piece of information.
Image below clearly illustrates the differences between centralized and distributed system.
In a distributed environment, no central company or person owns a system, yet everyone can use it and help running it. There is no single point of failure.
If you would like to read through a more detailed explanation, check out the free sample chapter from the book Blockchain Insider.
You may want to check out Bitcoin’s coding related info at https://github.com/bitcoin, or related documents at https://bitcoin.org/en/developer-documentation.