BLK102 · Cryptography Essentials for Blockchain

Categories: Emerging Technology
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About Course

Learn the three cryptographic building blocks behind every blockchain: hash functions, public-key cryptography and digital signatures, plus how wallets and keys really work.

Explore · 4 hours · 4 lessons, a lab, an assessed assignment and a portfolio piece

Who it is for

Learners who finished BLK101 and want to understand what keeps blockchain records and accounts secure.

Prerequisites

BLK101 or equivalent understanding of blocks and hashes.

What you will be able to do

  • Explain the properties of a cryptographic hash function and identify where blockchains use them
  • Generate a key pair and derive an address in a notebook, explaining each step
  • Sign a message and verify the signature, and explain why a signature proves authorization
  • Recommend key-management practices for a small business, including backup and recovery

Lessons

  • Lesson 1 · Hash functions and Merkle trees
  • Lesson 2 · Public-key cryptography, keys and addresses
  • Lesson 3 · Digital signatures and key management
  • Lesson 4 · Lab and assignment

Lab: Keys, signatures and Merkle roots in a notebook

You generate a throwaway key pair that never holds any funds, derive its address, sign a short business message and verify the signature. You then tamper with the message and watch verification fail. Finally, you build a small Merkle tree from four invoice records and compute its root.

Free tools: Google Colab (free) with Python hashlib and the open-source eth-account library

Assessed assignment

Write a two-page key-management guide for a fictional 12-person accounting firm that plans to sign documents and test-network transactions with its own keys. Explain in plain language what a private key, public key and address are. Recommend how keys should be generated, stored, backed up and recovered, and who may use them. Include a short incident plan for a lost or exposed key. Attach your lab notebook as evidence that you can sign and verify a message.

Criterion Weight What excellent work looks like
Accuracy of concepts 30% Explains keys, addresses, hashes and signatures correctly and without jargon overload.
Key-management recommendations 30% Gives specific, realistic practices for generation, storage, backup, access and rotation.
Incident plan 20% Describes clear first steps, responsibilities and communication if a key is lost or exposed.
Lab evidence 20% Notebook runs end to end and shows successful verification and a failed verification after tampering.

Portfolio piece

A working Colab notebook demonstrating signing, verification and a Merkle root, plus a key-management guide.

Self-paced, 12-month access. Questions are answered in writing through the student panel. A completion record is issued when you finish the course.

Next step

Continue with BLK103 · Smart Contracts and Decentralized Applications · 6 hours · $42.00

Continue to the next course

Prefer the whole program? Program in Blockchain, Web3 & Digital Identity · $277.00 (10% less than buying the courses separately)

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What Will You Learn?

  • Explain the properties of a cryptographic hash function and identify where blockchains use them
  • Generate a key pair and derive an address in a notebook, explaining each step
  • Sign a message and verify the signature, and explain why a signature proves authorization
  • Recommend key-management practices for a small business, including backup and recovery

Course Content

BLK102 · Cryptography Essentials for Blockchain (4 h)
Learn the three cryptographic building blocks behind every blockchain: hash functions, public-key cryptography and digital signatures, plus how wallets and keys really work.

  • Lesson 1 · Hash functions and Merkle trees
  • Lesson 2 · Public-key cryptography, keys and addresses
  • Lesson 3 · Digital signatures and key management
  • Lesson 4 · Lab and assignment
  • BLK102 Assessment · Cryptography Essentials for Blockchain
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