The primary purpose of a blockchain is to create a decentralized and tamper-proof ledger, where data is stored in a secure and transparent manner.

SHA-256 is a cryptographic hash function that is commonly used to secure blockchain transactions. It generates a unique and irreversible hash value for each transaction, ensuring its integrity.

A '51% attack' refers to an attempt by a single entity to gain control of a blockchain network by acquiring more than 50% of the network's computing power.

Smart contract exploits, phishing attacks, and distributed denial-of-service (DDoS) attacks are all common types of blockchain security vulnerabilities.

Consensus mechanisms play a crucial role in blockchain security by verifying the validity of transactions, preventing double-spending, and ensuring the integrity of the blockchain.

Proof-of-Work (PoW), Proof-of-Stake (PoS), and Delegated Proof-of-Stake (DPoS) are all examples of consensus mechanisms used in blockchain networks.

A private key in blockchain security serves multiple purposes, including encrypting transactions, verifying the ownership of cryptocurrencies, and generating public keys.

Using strong and unique passwords, enabling two-factor authentication (2FA), and storing private keys offline are all best practices for securing blockchain wallets.

Double-spending refers to a malicious transaction that attempts to spend the same cryptocurrency twice, typically by exploiting vulnerabilities in the blockchain network.

Smart contract audit, penetration testing, and vulnerability assessment are all common types of blockchain security audits.

A centralized blockchain is a blockchain network that is controlled by a single entity or a small group of entities, unlike decentralized blockchains which are controlled by a distributed network of participants.

Cryptocurrency, smart contracts, and decentralized autonomous organizations (DAOs) are all common types of blockchain-based applications.

A public blockchain is a blockchain that allows anyone to participate in the consensus process and add new blocks to the chain, unlike private blockchains which are controlled by a single entity or a small group of entities.

Sharding, layer-2 solutions, and off-chain transactions are all common types of blockchain scalability solutions.

A supply chain blockchain is a blockchain that is used to track the provenance and ownership of physical assets as they move through the supply chain.