Blockchain Fundamentals

Overview

A blockchain is a distributed, append-only ledger where blocks of transactions are cryptographically linked. Each block contains: transactions, previous block hash, timestamp, and nonce. Consensus mechanisms (PoW, PoS, BFT) ensure agreement without a central authority. Trade-off: decentralization vs performance.

When to Use

Trigger conditions:

• Evaluating whether blockchain is appropriate for a use case
• Designing systems requiring distributed trust, immutability, or transparency
• Understanding blockchain architecture for integration or development

When NOT to use:

• When a trusted central authority exists and works well (use a database)
• When performance (thousands of TPS) is the primary requirement
• When data privacy requires deletion capability (blockchain is append-only)

Algorithm