Public vs Private Blockchains: What’s the Difference?

If you're new to blockchain, you've probably heard people say things like “Ethereum is a public blockchain” or “Banks use private blockchains.”

Honestly, that can be super confusing, especially because the basic definition of blockchain already sounds public, right?

So... what does it really mean for a blockchain to be public or private?

In this article, I’ll break it down in simple terms and don’t worry, no tech background needed!

First, What Is a Blockchain?

Before we talk about public or private, let’s first get a grip on what a blockchain actually is.

A blockchain is a distributed ledger, which just means it’s a shared record that securely logs transactions across a network of computers.

Think of it like this:

Imagine a notebook that:

• is shared with a bunch of people,

• can only be updated when everyone agrees on what’s being written,

• and once something is written, it’s nearly impossible to change because everyone has a copy.

That’s basically what a blockchain is, a digital notebook where each page (called a block) holds data, and when it’s full, you flip to a new page and chain it to the last one.

Sounds pretty public by default, right?

So what’s with all this talk about “private” blockchains?

What Is a Public Blockchain?

Public blockchains are like open communities. They are:

• Permissionless (anyone can join)

• Transparent (everything is visible)

• Decentralized (no central boss)

  Imagine it like a public park, anyone can enter, walk around, and even plant flowers if they want. A public blockchain is just like that, anyone can:

  • Join the network

  • See the data (transactions, contracts, etc.)

  • Help run the network (by mining or validating)

Key Features:

• Open to everyone — you don’t need permission to use or participate

• Transparent — all transactions are publicly visible

• Decentralized — not controlled by any one person or company

• Slower & energy-intensive (sometimes) — because lots of people need to agree before anything is recorded

Examples:

• Bitcoin

• Ethereum

• Solana, Polygon, Avalanche, and others

Use Cases:

• Sending and receiving cryptocurrency

• Buying or selling NFTs

• Building and using decentralized finance (DeFi) apps

• Running community-governed projects (DAOs)

What Is a Private Blockchain?

Private blockchains are the opposite of that open park.

Think of them like an office building — you need an access card to get in, and only certain people are allowed to be part of what’s happening inside.

These blockchains are permissioned, meaning only selected people or organizations can:

• Join the network

• See the data

• Write to the ledger

They’re usually used by companies that need privacy, control, and speed.

Key Features:

• Restricted access — only approved participants can read or write

• Controlled — often run by one company or a small group

• Faster & more efficient — fewer people means quicker consensus

• Private — not all data is visible to the public

Examples:

• Hyperledger Fabric

• R3 Corda

• Quorum

Use Cases:

• Tracking goods in a supply chain (e.g., farm to supermarket)

• Internal banking systems

• Healthcare records and university credentials

• Legal contracts and audits

Which One is Better?

Honestly? Neither is “better.” It just depends on what you're trying to build.

• Use public blockchains if you want transparency, openness, and a global community (like for crypto, NFTs, or decentralized apps).

• Use private blockchains if you're a business that needs privacy, control, and speed (like for financial reporting or inventory management).

Conclusion

Now you know the difference:

• Public blockchain –– like a public street. Open to everyone. Transparent. Anyone can build or participate.

• Private blockchain –– like a private building. Only certain people are allowed in. Controlled and often faster.

Both are powerful, and in the real world, we’ll keep seeing more creative ways people use both — or even combine them to solve problems in finance, health, education, and beyond.

Thanks for reading! ✨