← Blockchain Teaching Resources

Cryptography Missions

Four short visual lessons showing how encryption, hashing and digital signatures protect blockchain transactions.

Mission 1 of 4 Step 1 of 7

Mission 1

One Secret Key

Symmetric encryption

Step 1

Alice has a confidential document

Alice needs to send a confidential business document to Bob. At the moment, the document is readable plaintext.

Key idea

Plaintext is the original readable information before encryption.

How the four ideas connect

🔒Encryption

Protects confidentiality by making information unreadable without the correct key.

#️⃣Hashing

Creates a fixed digital fingerprint that reveals whether data has changed.

✍️Digital signatures

Connect data to the private key that authorised it.

⛓️Blockchain

Uses hashes and signatures to verify and record authorised transactions.