Definition
Blockchain is a distributed, immutable ledger that records transactions across many computers. Each new transaction is grouped into a 'block' and cryptographically linked to the previous block, forming a 'chain.' This decentralized and transparent nature ensures data integrity and security without a central authority. In practice, it enables secure and verifiable record keeping, making it valuable for supply chain management, digital identity, and financial transactions. For instance, a blockchain can track the provenance of goods from origin to consumer, preventing fraud and ensuring authenticity. Unlike a traditional database that relies on a single point of control, blockchain's distributed nature makes it highly resistant to tampering. Understanding blockchain is increasingly important for professionals in cybersecurity and data management, appearing in domains like CompTIA Security+ and AWS Certified Security Specialty.