Welcome to Year 5 Computing — Lesson 6! 🔗💻
Today we are exploring the technology of the future: Blockchain! We will learn how Public and Private Keys act like digital signatures, and how a shared chain of blocks keeps our data completely safe from hackers.
Step 1: Keyboard Warm-up ⌨️ (10 Mins)
- Click here to warm up your fingers on our typing studio: Start Typing Practice on Ndovu.
- Today’s keywords: blockchain, ledger, public key, private key, signature, mining, transaction.
Step 2: Digital Signatures & Blockchain Simulators 🔐 (20 Mins)
Simulator 1: Digital Signatures ✍️
Goal: See how a private key acts like an unbreakable digital wax seal.
- Step 1: Type a message with a specific detail. (Examples: ‘Alice pays Pat 10 euros’, ‘Transfer 100 V-Bucks’, or ‘School ends at 3:15’).
- Step 2: Click Sign. This locks the message with a mathematical signature.
- Step 3: Become a hacker! Change a number or name in your message box.
- Step 4: Click Verify to see if the network catches your hack!
Security Status: Waiting for signature…
Simulator 2: Mine a Blockchain ⛏️
Goal: Understand why blockchains are unhackable. They rely on “Fingerprints” (hashes) that connect one block to the next.
- Step 1: Type a new transaction into Block 1 (e.g., ‘Give 50 gold to Sam’). Watch the fingerprint instantly change!
- Step 2: Click Mine Block 1. This locks the block and passes its fingerprint to Block 2.
- Step 3: Repeat for Block 2 (e.g., ‘Give 100 gold to Ali’), and then Block 3. Turn all blocks green!
- Step 4: The Hack: Go back to Block 1 and change ’50’ to ‘5000’. Watch how changing past data instantly breaks all the chain links!
Block 1
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Block 2
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Block 3
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Step 3: Video Reflection — Blockchain Societal Impact 🎬 (10 Mins)
Watch the video below to discover how blockchain is used in the real world outside of just money. Then, answer the reflection questions and download your report!
Step 4: Continue on Code.org 🚀 (15 Mins)
Now that you know how a blockchain stops hackers, let’s put it into practice on Code.org!
Mission: Launch Code.org Blockchain Unit
Click the button below to go directly to Lesson 2, Level 1 of your Blockchain module!
Launch Code.org Blockchain ➔Step 5: Log Off and Reflect 👋 (5 Mins)
- Exit Ticket: Why is it impossible for a hacker to change information in an old block without everyone on the network noticing?
- Log out securely and tidy your desk space!

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