Distributed ledger works differently than a typical database. The way it functions, when combined with blockchain, can make an effective security strategy.

Yesterday, we discussed what exactly blockchain is and how it works. By itself, blockchain is not a hyper-effective method of security because a bad actor can tamper with a block preceding the one that they want, re-hash everything and make it look like nothing happened. Enter distributed ledger. Distributed ledger is different than regular databases. The idea of distributed ledger is that you have a series of records and a series of data entry points spread across different machines, belonging to different owners. Generally speaking, when someone enters data at one of those data entry points and changes that data, the new copy goes to everyone. This is where the magic lies in distributed ledger.

Let’s look at a metaphor for an example. Pretend you send a Facebook message to a group of people saying hi. Facebook acts as a clearing house, they are the arbiter of data. Facebook captures your message and then sends a notification of that message and updates the UI of everyone in that group message. Now, if someone at Facebook wanted to take that message and alter it to say something else, you have zero control over that, you have no lens of validity. The integrity of the data is dependent on trusting the clearing house organization, a central body which controls where and how the data is stored. However, with distributed ledger one of the copies of the message chain gets the new input and then passes it along to all other copies. What that means is that everyone in the system is essentially talking to everyone else, adding data is distributed and synced. So in our metaphor, when you update the message to say hi, your system talks to your friend’s phones directly. When your friend says hi back, it would be sent to all of the other phones of the people in the group. Now everyone has the same message log (ledger) on their systems.

The problem with this goes hand-in-hand with the concept of blockchain. The problem with blockchain on its own is that while it can ensure integrity, it can be tampered with. The problem with distributed ledger is that anyone can tamper with their individual copy so that any of your friends can also change the messages to say something else. They could show this to someone and say it’s the truth. But when you combine them and create a distributed blockchain, potentially thousands of people have a copy of the ledger. They can prove which message is correct by looking at the hash that fits and the hash that doesn’t. Whoever has the hash that doesn’t match is wrong and tampering.

Using both blockchain and distributed ledger together makes it difficult for one or even a couple of people to tamper without setting off alarm bells. This is why distributed blockchain is so powerful. It not only makes hiding that you tampered with data difficult, but it also can point the finger at who or where that data was manipulated.