Types of Blockchain

🔗 Types of Blockchain

Imagine a digital notebook that thousands of computers share. Every time you write something new, everyone’s copy updates at the same time — and once written, it can never be erased or changed. That’s the heart of blockchain: a distributed, tamper-proof ledger.

Instead of one company or person controlling the data, the ledger lives on a network of computers (called nodes). They all agree on what’s true using clever math. You might have heard of Bitcoin or Ethereum — they’re just one flavour of blockchain.

Not all blockchains are the same. Some are open to the whole world, others are gated like a private club. Based on who can join, read, or write, we put them into three main baskets.

🌍 Public blockchain

Open to everyone · no permission needed · fully decentralised — like a park where anybody can walk in, play, and check the noticeboard.

anyone can join — no ID, no application. Download the software and you’re a node.
read & write for all — you can view every transaction and add new ones (if you follow the rules).
truly anonymous (pseudonymous) — no real identity required, just a wallet address.
secured by mining / staking — consensus mechanisms like proof-of-work keep it honest.
immutable & transparent — once data is added, it’s there forever, visible to the whole world.

🌟 famous examples Bitcoin, Ethereum, Solana, Cardano — all decentralised cryptocurrencies.

👍 best for: decentralised apps, censorship-resistant money, global transparency.

🔒 Private blockchain

One organisation rules · invitation-only · centralised control — think of a company’s internal database, but with blockchain flair.

single entity controls — a central authority decides who joins and what they can do.
read permissions may be restricted — the owner can let only certain people view the data.
ultra fast & efficient — since there are only a few trusted nodes, transactions are instant and cheap.
not truly decentralised — the controlling company can alter rules or even revert transactions (in theory).
great for internal audits — supply chain between subsidiaries, or internal record keeping.

🏢 examples Hyperledger Fabric (when used by one org), R3 Corda (private mode), internal bank ledgers.

👍 best for: enterprise databases, intra‑company tracking, speed over decentralisation.

🏛️ Permissioned (consortium) blockchain

Semi‑private · multiple pre‑approved organisations · hybrid vibe — like a gated community where a few trusted members run the show together.

consortium/governed by a group — not one company, but a handful of known players (banks, insurers, etc).
nodes are pre‑approved — you can’t just show up; you need an invitation from the members.
faster than public, more trusted than private — consensus is lightweight because all validators are known.
partial decentralisation — power is distributed among the consortium, not the general public.
read permissions can be layered — sometimes the public can read limited data, but writing is restricted.

🤝 examples IBM Food Trust (Walmart, Nestlé…), Marco Polo (trade finance), B3i (insurance consortium).

👍 best for: industry collaboration, supply chains with multiple partners, regulated finance.

✨ quick comparison at a glance ✨

🌍 public

no gatekeeper, anyone can read/write, slow but secure

🔒 private

centralised, fast, one boss, like a traditional db with hashes

🏛️ permissioned

group‑controlled, trusted participants, balanced

🧩 why does the type matter?

Choosing the right blockchain depends on what you’re building. If you want uncensorable money → public. If a bank wants to settle internal transfers → private. If ten shipping companies need to share a trusted system → permissioned.

And remember — even though private/permissioned blockchains reuse some tech from Bitcoin, they’re often closer to shared databases. But they still give you auditability, encryption, and tamper evidence.