A compact data structure containing essential metadata including version numbers, difficulty targets, and cryptographic references that enable other nodes to quickly verify the block's legitimacy

A unique 256-bit identifier that cryptographically links this block to its predecessor, creating an unbreakable chain where altering any previous block would immediately be detected

A single hash that mathematically represents all transactions in the block, allowing quick verification that no transactions have been tampered with since the block was created.

Records the exact moment when the block was mined, enabling the network to maintain chronological order and enforce time-based rules.

A 32-bit "number used once" that miners continuously modify during the mining process to find a hash that meets the network's difficulty requirements.

The storage area containing the actual transaction data, digital signatures, and smart contract executions that users initiated.

Blocks are cryptographically linked in chronological order: Each new block mathematically depends on all previous blocks through hash references, creating a timeline that cannot be altered without detection.

Each block references the hash of the previous block: This creates a dependency chain where changing any historical block would require recalculating every subsequent block's hash.

This creates an unbreakable chain of data: The mathematical impossibility of reverse-engineering hash functions means that once blocks are linked and confirmed, they become practically immutable.

The genesis block is the first block with no predecessor: This special foundational block is hardcoded into the blockchain protocol and serves as the starting point for the entire chain.

When someone wants to send cryptocurrency or execute a smart contract, they create a digitally signed transaction and transmit it to multiple network nodes simultaneously.

Each transaction contains complete information needed for validation, including cryptographic proof that the sender authorized the transfer.

Thousands of computers across the network independently check that transactions follow proper protocols and contain all required fields.

Approved transactions are temporarily stored in each node's memory until miners or validators select them for inclusion in the next block.

Block creators choose which pending transactions to include, often prioritizing those with higher fees to maximize their rewards.

Transactions are arranged in a specific format with proper headers, merkle tree organization, and required metadata.

Most blockchains impose size restrictions (like Bitcoin's 1MB limit) to prevent blocks from becoming too large for the network to handle efficiently.

Block creators balance including high-fee transactions with technical constraints to optimize their economic returns.

Each transaction must be cryptographically signed by the sender's private key, proving ownership and authorization without revealing the private key itself.

The network verifies that senders actually possess the cryptocurrency they're attempting to transfer, preventing overdrafts and fraudulent transactions.

Every transaction must follow specific data structures, field requirements, and protocol standards established by the blockchain's consensus rules.

The network maintains a record of all unspent transaction outputs (UTXOs) and rejects any transaction that tries to spend the same cryptocurrency twice.

Thousands of specialized computers (miners) race to solve cryptographic puzzles that require immense computational power, with the winner earning the right to add the next block and receive cryptocurrency rewards.

Mining requires dedicated hardware (ASICs) consuming significant electricity, creating a real-world cost that anchors digital security to physical resources and energy expenditure.

The miner who first discovers a valid solution broadcasts it to the network, and other miners immediately verify and accept the solution, starting work on the next block.

Other network participants can quickly verify the winning solution (taking milliseconds versus hours to find), ensuring the winner followed the rules without requiring the same computational effort.

Bitcoin pioneered this method in 2009, followed by Litecoin, Dogecoin, and Ethereum (before its 2022 transition), proving the mechanism's reliability across different cryptocurrencies.

Validators are chosen to create new blocks based on the amount of cryptocurrency they "stake" (lock up as collateral), creating a system where those with the most to lose from network failure have the most influence over its operation.

Unlike mining's massive electricity consumption, PoS requires only standard computer hardware running lightweight software, reducing energy usage by over 99% compared to Proof of Work systems.

Validators must deposit significant amounts of cryptocurrency as stake, which can be "slashed" (permanently confiscated) if they attempt to validate fraudulent transactions or attack the network.

Advanced cryptographic algorithms randomly select validators from the pool of stakers, with higher stakes increasing selection probability while preventing any single entity from controlling block production.

Ethereum successfully transitioned to PoS in 2022, joining Cardano, Polkadot, and Solana in demonstrating that this mechanism can secure billions of dollars in value while maintaining decentralization.

Token holders vote for delegates who will represent their interests, similar to electing representatives in political systems, ensuring that validation power reflects community preferences.

A limited number of elected delegates (typically 21-101) handle transaction validation, enabling faster processing than systems where thousands of nodes must reach consensus.

Fewer validators mean quicker decision-making and higher transaction throughput, making DPoS suitable for applications requiring rapid confirmation times.

Delegates can be voted out for poor performance, creating ongoing incentives for honest behavior and responsive service to the community.

Network operators select validators based on identity verification and reputation, ensuring only trusted parties can participate in consensus decisions.

Commonly deployed in private blockchains for supply chain tracking, corporate record-keeping, and government applications where regulatory compliance is essential.

Eliminates competitive mining or staking, enabling near-instantaneous transaction confirmation with minimal computational overhead.

Security relies on the established reputation and legal accountability of validator organizations rather than cryptoeconomic incentives.