Ledger

The accounting layers of most blockchains are simply public ledgers with rules. With digital signatures and irreversible cryptography, anyone can record the movement of value without needing to depend on a central mediating authority. You might maintain a ledger among your friends. It might be written down or just remembered. Since there isn’t much to keep track of, and hopefully you trust your friends to honor their transaction, its an effective tool for small exchanges of value. A blockchain is that concept at scale. Alice can sign her transaction to Bob and everyone with a copy of the Ledger knows that transaction is legitimate. This allows Bob to go on and spend the Bitcoin he got from Alice, and it will always be honored. The most obvious difference between cryptocurrency and a friendly ledger is that you can’t take a cryptocurrency ledger into debt. You buy into the ledger with fiat currency from anyone willing to make the exchange. You can think of cryptocurrency as a tokenized version of money. But when you get might down to it, money is just a tokenized version of confidence and value.