What is a block?

You may recall from my last article, The blockchain explained. In simple terms… that the blockchain is made up of transactions called blocks. But, what exactly is that? Let’s take a look.


Each block or collection of transactions during a specific time period are grouped together. Once these transactions are grouped together, the block is given a timestamp and a reference to the block that came before it. Think of a block as a brick with a date stamped on it, and the mortar between the bricks would be the reference to the previous brick so that there is a linear, chronological progression of blocks, or in this case, bricks.


The blockchain is secure in part because of the way the blocks are connected to each other with a timestamp and a reference to the previous block. For example, let’s say someone wanted to hack the blockchain. They would have to not only forge/copy the block they’re trying to steal, but also every single previous one in the chain.

If these two elements did not exist, the blockchain would simply be a group of unrelated transactions floating around on a network somewhere, easily picked off, one by one, by a hacker.


To wrap things up thus far using the checkbook analogy, we have a checkbook (blockchain), that has groups of transactions (blocks) with a timestamp and reference to the group before it. And if someone wanted to steal one of those transactions, they would have to counterfeit every single transaction ever created in that checkbook. Next, we’ll discuss miners and how they provide value and security to the blockchain.

-The Crypto Fizz Team