Understanding Bitcoin: The Fundamentals of Cryptocurrency
Image source: Bitcoin Fundamentals: Structure, Scarcity and Use - Morgan Stanley
Bitcoin is a decentralized digital currency that lets people send value directly to each other without a bank in the middle. It works by combining wallets, cryptographic signatures, a public transaction ledger, and a consensus process called mining. 1, 5
Core idea
A Bitcoin wallet creates a public address for receiving funds and a private key for controlling them. When you send bitcoin, your wallet signs the transaction with your private key so the network can verify that you are authorized to spend those coins. 6, 1
How transactions move
- A user creates a transaction in a wallet.
- The wallet signs it with the private key.
- The transaction is broadcast to the network.
- Miners collect pending transactions into a block.
- The network validates the block and adds it to the blockchain. 5, 1, 6
Why it is secure
Bitcoin uses cryptography to make transactions hard to forge or alter. The blockchain is a shared public ledger, so once a transaction is confirmed and buried under later blocks, changing it would require redoing the work for that block and all that follow. 1, 5, 6
What mining does
Mining is the process that confirms transactions and orders them chronologically. It also helps prevent double spending by making it very difficult for someone to rewrite history and spend the same bitcoin twice. 6, 1
Supply and scarcity
Bitcoin’s protocol caps total supply at 21 million coins, and new bitcoin are issued at a slowing pace through block reward halvings. That fixed supply is one reason people describe Bitcoin as digitally scarce. 7, 5
Practical takeaway
Think of Bitcoin as a global payment and settlement system built on three layers: ownership proven by private keys, records kept on a public blockchain, and consensus enforced by mining. That combination is what makes it work without a central operator. 1, 6