Blockchain and Cryptocurrency
A blockchain is a shared digital ledger of linked blocks of records that is hard to change, and it underpins cryptocurrencies like Bitcoin.
▶ Interact
Play with the controls to see the idea in action.
📘 Learn
A blockchain is a shared digital ledger of linked blocks of records that is hard to change, and it underpins cryptocurrencies like Bitcoin.
- Blocks are linked by hashes
- No central authority is needed
- Mining validates transactions
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Blockchain and Cryptocurrency?
Within Computer Science, which covers algorithms, programming, data, networks, hardware and safe, responsible use of technology, this topic explains Blockchain and Cryptocurrency. Computing topics explain how software, hardware and data work, with diagrams and models that show each step in order.
Check that you can explain Blockchain and Cryptocurrency in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Blockchain and Cryptocurrency helps you design, test and explain programs, websites and systems, from small projects to exam questions.
Blockchain and Cryptocurrency in detail
A blockchain is a digital ledger, a chain of blocks of records, shared across many computers (a distributed network). Each block contains transactions and a cryptographic hash of the previous block, so changing one block would change all later ones, and so tampering is easy to spot and very hard to carry out.
Cryptocurrencies such as Bitcoin use blockchain to record transactions without a bank or central authority, with people called miners validating them. Blockchains are also used for supply chains, contracts and records. Concerns include the large energy use of some systems, price volatility, scams and legal uncertainty.
How the interactive helps you understand Blockchain and Cryptocurrency
Watch the network in the interactive. Use any sliders or buttons it offers to change the values and see how the network responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Blockchain and Cryptocurrency.
Real-life uses and examples
- Explain Blockchain and Cryptocurrency to someone new to computing by comparing it to a familiar process.
- Trace through a process that uses Blockchain and Cryptocurrency to check what it does step by step.
- Recognise Blockchain and Cryptocurrency in an app or device you use every day.
Common mistakes to avoid
- Using the term without being able to say what the computer actually does.
- Testing only the normal case and forgetting the edge cases.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Blockchain and Cryptocurrency
What is Blockchain and Cryptocurrency?
A blockchain is a shared digital ledger of linked blocks of records that is hard to change, and it underpins cryptocurrencies like Bitcoin.
What are the most important points about Blockchain and Cryptocurrency?
The main points are: Blocks are linked by hashes; No central authority is needed; Mining validates transactions.
Why is Blockchain and Cryptocurrency useful?
Understanding Blockchain and Cryptocurrency helps you design, test and explain programs, websites and systems, from small projects to exam questions.
How can I practise Blockchain and Cryptocurrency?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Blockchain and Cryptocurrency?
Related topics in Computer Science include Quantum Computing Basics, APIs and Web Services, Data Structures: Stacks and Queues.