ELI5: Explain Like I'm 5

blockchain

Blockchain is a type of technology that helps keep track of information. It is like a big ledger that records information permanently so that it is always safe and secure. It is like a long chain of blocks (like toy building blocks). Each block in the chain holds a list of information that is connected to the blocks before and after it, allowing them to all be linked together. This makes it so that the information can't be changed or deleted. That is why it is so secure.