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What is Blockchain?
Blockchain — A distributed ledger technology that records transactions in sequential blocks linked by cryptography, maintained by a decentralized network of nodes.
How It Works
01 Transactions are grouped into blocks; each block contains a cryptographic hash of the previous block, forming a chain.
02 Network nodes validate transactions and reach consensus on the order and validity of blocks.
03 Once a block is added, it cannot be altered without redoing all subsequent blocks — making the ledger immutable.
04 Consensus mechanisms (Proof of Work, Proof of Stake) ensure all nodes agree on the state without trust.
Why It Matters
▸ Blockchain enables trustless transactions — parties can transact without knowing or trusting each other.
▸ It provides transparency: public blockchains allow anyone to audit the entire transaction history.
▸ Immutability prevents tampering, making blockchain useful for finance, supply chain, and identity.
▸ It removes single points of failure — no central server can be hacked or shut down.
Common Questions
Is blockchain the same as Bitcoin?
No. Bitcoin is a cryptocurrency built on blockchain technology. Blockchain is the underlying technology that can power many applications beyond crypto.
Can blockchain be hacked?
A well-established blockchain (like Bitcoin) has never been hacked. Weaknesses lie in exchanges, wallets, and smart contracts — not the blockchain protocol itself.
What are consensus mechanisms?
Methods by which nodes agree on the blockchain state. Proof of Work (mining) and Proof of Stake (staking) are the two most common.