BASICS5 min read

What is Blockchain?

Name: Awarizon SDK
Author: Awarizon

The distributed ledger technology that makes Web3 possible

A blockchain is a digital record book shared across thousands of computers worldwide. No single person, bank, or government controls it. Once data is written to the blockchain, it cannot be changed or deleted — ever.

The simple explanation

Imagine a Google Doc that thousands of people share — but instead of being editable, every entry is permanent. And instead of Google controlling the server, no single company does. That is essentially what a blockchain is.

Data is grouped into "blocks." Each block contains a batch of transactions plus a unique fingerprint (called a hash) of the previous block. This links every block to the one before it — forming a "chain." If anyone tries to alter an old block, it changes that block's hash, which breaks its link to every block that came after it. The tampering becomes instantly obvious to the entire network.

💡Key insight

The security of a blockchain comes not from a single trusted entity, but from mathematics and distributed consensus. Changing the record would require controlling over 50% of all computing power on the network simultaneously — which is practically impossible on large blockchains.

When someone sends crypto or executes a smart contract, the transaction is broadcast to the network. Thousands of computers (called nodes) receive this transaction and validate it — checking that the sender has sufficient funds and that the transaction is correctly signed.

01Transaction is created and signed by the sender's private key
02The transaction is broadcast to all nodes on the network
03Nodes validate the transaction (checking balances, signatures)
04Valid transactions are grouped into a candidate block
05A consensus mechanism (mining or staking) determines which node adds the block
06The block is added to the chain and distributed to all nodes
07The state of the blockchain is updated globally

In traditional systems, you trust intermediaries — banks to hold your money honestly, governments not to inflate the currency, companies not to freeze your account. Blockchain replaces this trust with code and mathematics.

The rules of the network are written into the protocol. Everyone can read them. Nobody can override them — not even the people who created the blockchain. Your money is controlled by your private key, and only your private key.

ℹTrustless ≠ No trust required

"Trustless" means you do not need to trust a specific person or company. You still trust the code — but the code is open-source and audited by thousands of developers worldwide.

Public Blockchains

–Anyone can join and participate
–Fully transparent — all transactions visible
–Decentralized — no single controller
–Examples: Bitcoin, Ethereum, Solana

Private Blockchains

–Access controlled by an organization
–Transactions can be private
–More centralized but more efficient
–Examples: Hyperledger, Quorum

There are also "Layer 2" networks (like Polygon, Arbitrum, Optimism) that run on top of public blockchains to make transactions faster and cheaper — while still settling final security on the main chain.

KEY TERMS GLOSSARY

Block

A container holding a batch of validated transactions plus metadata (hash, timestamp, previous hash).

Hash

A unique digital fingerprint generated from any piece of data. Changing the data changes the hash entirely.

Node

A computer participating in the blockchain network, storing a full copy of the ledger.

Consensus

The process by which all nodes in the network agree on which transactions are valid and in what order.

Immutability

The property of blockchain data that makes it permanent and unchangeable once confirmed.

Decentralized

Distributed across many nodes with no single point of control or failure.

What is Blockchain?

The simple explanation

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