# What is blockchain and how can I use it?

Jessica Washington · August 4, 2026

> Blockchain was first conceptualized in 1991 by researchers Stuart Haber and W. Scott Stornetta, but it wasn't until 2009 that it was implemented in...

Blockchain was first conceptualized in 1991 by researchers Stuart Haber and W.

Scott Stornetta, but it wasn't until 2009 that it was implemented in practice with the creation of Bitcoin.

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Blockchain is a decentralized, distributed digital ledger that records transactions across many computers in a network.

This makes it resistant to modification of the data.

Each "block" on the blockchain contains a number of transactions, and every time a new transaction occurs, a record of that transaction is added to every participant's ledger.

The blockchain network has no central authority - it is the very definition of a distributed system.

This means there is no single point of failure and no single entity can control the data.

Transactions on the blockchain are verified by network nodes and recorded in a public distributed ledger called a blockchain, which cannot be altered.

This provides transparency.

Blockchains use cryptographic techniques like hashing and digital signatures to secure the network and prevent fraud.

This makes them extremely secure.

Beyond cryptocurrencies, blockchains can be used to track the provenance of goods, record land titles, manage supply chains, and even store medical records and voting information.

Smart contracts are self-executing contracts with the terms of the agreement between buyer and seller directly written into lines of code.

These can automate many processes.

Each block contains a cryptographic hash of the previous block, which ties the blocks together and prevents anyone from tampering with the ledger.

Blockchain transactions are pseudonymous - users are not identified by name but rather by blockchain addresses, which are randomly-generated numbers.

The distributed nature of blockchains means they have no single point of failure.

If one node goes down, the rest of the network can continue to function.

Miners are the backbone of blockchain networks.

They use powerful computers to solve complex mathematical problems to verify transactions and add them to the blockchain.

The blockchain is constantly expanding as new blocks are added to the end of the blockchain, acting as a never-ending, append-only public record of transactions.

Blockchains are immutable, meaning that once data is recorded, it cannot be altered or deleted.

This makes them very useful for record-keeping and traceability.

While blockchains are secure, they are not perfectly secure.

There have been cases of hacks and thefts, usually targeting the exchanges where people store their digital currencies.

The energy consumption of some blockchain networks, like Bitcoin, has raised environmental concerns due to the computing power required for mining.

Interoperability is a challenge - different blockchain networks often can't communicate or share data with each other, limiting the potential for integration.

Blockchains can be public (permissionless) or private (permissioned), depending on who is allowed to participate in the network and maintain the shared ledger.

Scalability is another issue, as the number of transactions that can be processed per second on a blockchain is limited compared to traditional centralized systems.

Regulation of blockchain and cryptocurrencies is still evolving, with governments around the world taking different approaches, creating uncertainty for users and businesses.

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