Blockchain

A distributed digital ledger that records transactions across a network of computers.

A blockchain is a decentralized, distributed digital ledger that records transactions across many computers in a way that makes it nearly impossible to alter retroactively. Each "block" contains a batch of transactions, and blocks are cryptographically linked together in a "chain."

How It Works

When a transaction is initiated, it is broadcast to a network of nodes. These nodes validate the transaction using consensus mechanisms (like Proof of Work or Proof of Stake). Once validated, the transaction is grouped with others into a block and added to the chain permanently.

Key Features

Immutability: Once data is recorded, it cannot be easily changed without altering all subsequent blocks.

Transparency: All transactions are publicly visible on the blockchain.

Decentralization: No single point of failure — the ledger is maintained by thousands of nodes.

Security: Cryptographic hashing ensures data integrity.

Beyond Cryptocurrency

While blockchain technology was originally created for Bitcoin, it has since been applied to supply chain management, voting systems, identity verification, healthcare records, and much more.

Frequently Asked Questions

What is a blockchain?

A blockchain is a decentralized, distributed digital ledger that records transactions across many computers. Data is stored in blocks that are cryptographically linked together, making it nearly impossible to alter historical records.

How does blockchain technology work?

Transactions are broadcast to a network of nodes, validated using a consensus mechanism, grouped into blocks, and permanently added to the chain. Each block references the previous block's hash, creating an immutable record.

What are blockchains used for besides cryptocurrency?

Blockchain technology is applied to supply chain tracking, digital identity verification, voting systems, healthcare records, real estate tokenization, and decentralized finance (DeFi).

Is blockchain data really immutable?

On well-established networks like Bitcoin and Ethereum, practically yes. Altering historical data would require re-mining or re-validating every subsequent block, which is computationally and economically infeasible on large networks.

Related Terms

Address

A unique alphanumeric identifier representing a destination for sending or receiving cryptocurrency.

Atomicity

The property ensuring a transaction either completes fully or doesn't execute at all.

Bitcoin

The first and largest cryptocurrency, created by Satoshi Nakamoto in 2009.

Block

A container of transaction data that is permanently recorded on a blockchain.

Block Explorer

A web tool for searching and viewing blockchain transactions, addresses, and blocks.

Block Height

The sequential number of a block in the blockchain, counting from the genesis block.

Coin

A cryptocurrency that operates on its own native blockchain network.

Consensus Mechanism

The system used by blockchain networks to agree on the validity of transactions.

Cryptocurrency

A digital or virtual currency secured by cryptography on a blockchain network.

Cryptography

The use of mathematical techniques to secure communications and validate blockchain transactions.

DLT

Distributed Ledger Technology — shared, synchronized databases spread across multiple locations.

Double Spending

The risk of spending the same digital currency unit more than once.

Fork

A change in a blockchain's protocol that creates a divergent version of the network.

Genesis Block

The very first block ever mined on a blockchain network.

Immutable

A property of blockchain data meaning it cannot be changed or deleted once recorded.

Interoperability

The ability of different blockchain networks to communicate and share data with each other.

Layer 1

A base blockchain network like Bitcoin, Ethereum, or Solana.

Mainnet

The primary, live blockchain network where real transactions are processed.

Node

A computer connected to a blockchain network that validates and relays transactions.

On-Chain

Transactions or data that are recorded directly on the blockchain.

Peer-to-Peer

Direct interactions between parties without a central authority or intermediary.

Proof of Authority

A consensus mechanism where approved validators verify transactions based on their identity.

Quantum Resistance

The ability of cryptographic systems to remain secure against quantum computer attacks.

Satoshi Nakamoto

The pseudonymous creator of Bitcoin whose real identity remains unknown.

Scalability

The ability of a blockchain network to handle increasing demand and transaction volume.

Sharding

A database partitioning technique that splits a blockchain into smaller, parallel segments.

Soft Fork

A backward-compatible upgrade to a blockchain's protocol.

Zombie Chain

A blockchain that continues to operate despite being abandoned by developers and users.