Congratulations! You just learned the basics of blockchain technology. Below is a review of important terms that you may want to study to further solidify your knowledge on the blockchain.

Let’s remember the vocabulary we learned

  • Blockchain: A blockchain is an accurate and permanent record of transactions that have been verified and stored in a chronological sequence.
  • Blocks: A block is an individual transaction or piece of data that is being stored within the blockchain.
  • Blockchain Network: The blockchain network and blockchain are terms used interchangeably. They represent the entire blockchain from the structure itself to the network that it is a part of.
  • Decentralization: The concept in which users work together to validate transactions without relying on a central authority.
  • Participant: A client that owns a copy of the blockchain and verifies transactions across the network.
  • Deterministic: The same input will always produce the same output, but that output will never produce the original input.
  • Hash: A fixed-length string of a varying combination of letters and numbers produced from a specific input of arbitrary size.
  • Hash Function: A function that takes in an input of a random size, performs hashing on this input, and generates a random output of a fixed size, also known as the hash.
  • Genesis Block: The genesis block is the first block on the blockchain and it is typically hard-coded into the blockchain structure. Being the first block on the blockchain, it does not have a link to a previous hash.

Block Properties

  • Timestamp: The time the block is created determines the location of it on the blockchain.
  • Data: The information to be securely stored in the block.
  • Hash: A unique code produced by combining all the contents within the block itself — also known as a digital fingerprint.
  • Previous Hash: Each block has a reference to the block prior to its hash. This is what makes the blockchain unique because this link will be broken if a block is tampered with.


The visualization represents the basic properties and structure of a blockchain. Go ahead and hit Submit Data for each of the blocks.

After that, try and tamper with the block in the middle. What happens when the block is updated?

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