What Is Blockchain?
Blockchain is a special kind of digital database or ledger. But unlike a normal database (like Excel or Google Sheets), it has three unique characteristics:
It's decentralized (not controlled by one person or company),
It's secure and tamper-proof, and
It's built with blocks of data that are chained together in order.
🗳️ 1. Understanding Consensus Mechanisms
Consensus mechanisms are how blockchain networks agree on what's true — without a central authority like a bank or government.
🔍 How I Understood It:
Think of it like a group chat of friends trying to decide where to meet. Everyone has a say, but you need a fair system so people don’t vote twice or lie. Blockchain has to reach agreement (consensus) every time someone adds a new transaction.
💡 Common Consensus Types:
Proof of Work (PoW): Like solving a complex puzzle. Whoever solves it first gets to add the next block. It's secure but slow and uses a lot of energy.
Proof of Stake (PoS): Like picking validators based on how many tokens they’ve locked (or “staked”) as a sign of trust.
Delegated Proof of Stake (DPoS) (used by Lisk): Instead of everyone trying to validate, token holders vote for a small group of “delegates” to validate blocks on behalf of the network.
🧠 For me, DPoS felt like classroom group work — instead of everyone shouting answers, the class elects a few trusted students to speak and represent everyone fairly.
💻 2. Nodes and Clients
A node is a computer that runs the blockchain software and helps maintain the network.
🧠 My Understanding of Nodes:
I thought of nodes like editors in a shared Google Doc — they check every update to the document and make sure it follows the rules. Some editors have full access to the whole history, while others only see current versions.
🔧 Types of Nodes:
Type Explanation
Full Node Stores the entire blockchain and validates all transactions. Like having the whole document history.
Archive Node Keeps every past state — even data that's not needed anymore, in case you want detailed analysis. Like having a time machine for the document.
Each node uses software called a client. In Lisk, the client is powered by the Lisk SDK, which developers can use to build, run, and customize their own blockchains.
🏛️ 3. DAOs — Decentralized Autonomous Organizations
A DAO is like a company that runs on code instead of managers.
🧠 How I Understood It:
Imagine a club where every rule, decision, and vote is written into a smart contract. Members don’t rely on a president or CEO — everything is voted on, and the results are automatic.
In DAOs:
Proposals are made by members
Votes happen on-chain
Rules are enforced automatically by smart contracts
🎯 I pictured a DAO like a community-run vending machine — everyone votes on what snacks to restock, and the vending machine updates itself based on those votes, no human needed.
🔓 4. Public vs Private Blockchains
At first, I was confused about why we even have private blockchains if the whole point is decentralization. Here’s what I learned:
🌍 Public Blockchains:
Anyone can join, view, or participate
Decentralized and transparent
Examples: Lisk, Ethereum, Bitcoin
🏢 Private Blockchains:
Restricted access — only authorized users can join
Common in enterprise, banking, or internal systems
Faster and more controlled, but less transparent
🔐 I saw public blockchains like public libraries — open for anyone. Private blockchains are like company databases — only employees have keys to enter.
🔁 5. Hashing: The Blockchain Glue
Hashing was a tricky one at first, but this is how I got it.
🧠 My Understanding of Hashing:
Hashing takes any input (a file, message, or block) and converts it into a unique string of letters and numbers. It’s a one-way street — you can’t reverse it to get the original.
Example:
Input: "Hello world"
Hash (using SHA-256): a591a6d40bf420404a011733cfb7b190...
Even a small change in the input changes the entire hash.
💡 Why It's Used:
Each block’s hash depends on the previous one, forming a secure chain.
It guarantees that the data hasn’t been changed.
It helps with fast verification.
🧩 I thought of hashing like a digital fingerprint — two people (or files) can’t have the same one. If the fingerprint changes, the file has changed.
🔐 6. Cryptography and Security
At the heart of blockchain is cryptography — it keeps our wallets, transactions, and identities safe.
🧠 My Understanding:
Each user has a private key (like a password) and a public key (like a username). You sign transactions with your private key, and others can verify it with your public key.
🖊️ Digital Signatures:
When you sign a transaction, it proves you made it and no one changed it.
Others on the network can verify the signature without needing to trust you personally.
🧠 It helped me to compare it to sending a sealed, signed envelope — only you could’ve sealed it, and anyone can check the seal is genuine.
🧠 Summary: What I Took Away
Concept What I Learned
Lisk A JavaScript-friendly blockchain for building apps
Consensus Blockchain’s way of agreeing on truth
Nodes Computers keeping the network alive and honest
DAOs Online communities governed by smart contracts
Public vs Private Chains Open vs restricted systems
Hashing A way to secure and verify data
Cryptography Math-powered security that replaces human trust
🙌 Final Thoughts
This session of the Lisk Summer Bootcamp helped me go from “blockchain sounds cool” to “I actually get what makes it work.” Each concept built on the last, and using analogies helped me connect it to the real world.
If you’re starting your blockchain journey, I highly recommend attending a bootcamp like this — it’s beginner-friendly, well-paced, and you learn by doing, not just reading.
Thanks for reading! Let’s keep learning and building together. 💙
💬 Over to You
Have you learned any of these concepts recently? Which one confused you the most when starting out?
Let’s chat in the comments!
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