> For the complete documentation index, see [llms.txt](https://davidjosearaujo.gitbook.io/online-courses/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://davidjosearaujo.gitbook.io/online-courses/blockchain-security/fundamentals-of-blockchain-security/introduction-to-blockchain.md).

# Introduction to blockchain

## What is the blockchain?

Blockchain was invented over a decade ago by Satoshi Nakamoto

It implements as immutable and decentralized data storage mechanism using:

* Cryptographic primitives
* Existing data structures (e.g., Merkle trees)
* Computer science concepts (e.g., proof of work)

By combining a number of existing theories, algorithms and data structures in a new way, Nakamoto created blockchain

* The guarantees that blockchain provides make it an active area of research in many startups and large firms