Cryptocurrency is digital money that uses cryptography and shared computer networks instead of a central bank to record ownership and payments. It matters in economics because it creates new ways to transfer value, raise capital, build financial services, and store wealth across borders. Bitcoin and Ethereum are the two best-known examples, but they serve different roles in the digital economy.
Understanding cryptocurrency requires connecting money, incentives, networks, risk, and trust.
Key Facts
- A blockchain is a shared ledger where transactions are grouped into blocks and linked in time order using cryptographic hashes.
- Bitcoin supply is capped at 21,000,000 BTC, which makes scarcity a central part of its economic design.
- Market capitalization = coin price x circulating supply.
- Transaction fee = total amount paid by sender - amount received by recipient, often used to reward miners or validators.
- Public key cryptography lets users receive funds with a public address and spend funds only with the matching private key.
- Ethereum supports smart contracts, which are programs that run on the blockchain when specified conditions are met.
Vocabulary
- Blockchain
- A blockchain is a decentralized digital ledger that records transactions in linked blocks shared across many computers.
- Wallet
- A wallet is software or hardware that stores private keys and lets a user send, receive, and manage cryptocurrency.
- Private Key
- A private key is a secret code that proves ownership of cryptocurrency and authorizes transactions.
- Mining
- Mining is the process used in some blockchains, such as Bitcoin, where computers compete to validate transactions and add new blocks.
- Smart Contract
- A smart contract is a self-executing blockchain program that follows rules written in code.
Common Mistakes to Avoid
- Confusing a wallet with a bank account is wrong because a wallet usually stores keys, not the coins themselves. The coins are recorded on the blockchain.
- Sharing a private key or seed phrase is a serious mistake because anyone with it can control the funds. There is usually no customer service that can reverse the loss.
- Assuming all cryptocurrencies work like Bitcoin is wrong because networks differ in supply rules, transaction speed, governance, and purpose. Ethereum, for example, focuses on programmable contracts as well as value transfer.
- Ignoring transaction fees is a mistake because fees can change with network demand. A small transfer can become expensive when the network is congested.
Practice Questions
- 1 A cryptocurrency has a price of $2,400 and a circulating supply of 120,000,000 coins. Calculate its market capitalization.
- 2 You send 0.750 ETH to a friend, and the network fee is 0.006 ETH. How much ETH leaves your wallet in total?
- 3 Explain why a blockchain can allow strangers to agree on transaction history without trusting one central company.