Cryptocurrency is digital money secured by cryptography and recorded on a blockchain. No bank issues it. No government backs it. The rules are in the code, and the ledger is public. Bitcoin was the first. Thousands have followed, each with different features and trade-offs.

The cryptography does two things. It proves that a transaction was authorized by the holder of a private key. And it links blocks together so that past records cannot be altered without detection. That combination creates a system where value can move across the world without an intermediary. The sender and receiver do not need to trust each other. They only need to trust the protocol. The price of that trustlessness is volatility. Crypto markets swing hard, and there is no central bank to smooth the ride. A coin can lose half its value in a week and nobody can stop it.

Core properties

• Decentralized — no single issuer or controller
• Cryptographically secured — private keys authorize transfers
• Transparent — transactions are publicly auditable
• Volatile — prices fluctuate sharply

Cryptocurrency is not good at everything. It is slow compared to a credit card and complicated for everyday use. It is good at moving value without permission and resisting censorship. That is the niche.