Cryptocurrencies, sometimes called virtual currencies, digital money/cash, or tokens,are not really like U.S. dollars or British pounds. They live online and are not backed by a government. They’re backed by their respective networks. Technically speaking, cryptocurrencies are restricted entries in a database. Specific conditions must be met to change these entries. Created with cryptography, the entries are secured with math, not people.
Restricted entries are published into a database, but it’s a special type of database that is shared by a peer-to-peer network. For example, when you send some Bitcoin to your friend Cara, you’re creating and sending a restricted entry into the Bitcoin network. The network makes sure that you have not created the same entry twice; it does this with no central server or authority. Following the same example, the network is making sure that you didn’t try to send your friend Cara and your other friend Alice the same Bitcoin.
The peer-to-peer network solves the “double-spend” problem (you sending the same Bitcoin to two people) in most cases by having every peer have a complete record of the history of all the entries made within the network. The entire history gives the balance of every account including yours. The innovation of cryptocurrency is to achieve agreement on what the history is without a central server or authority.
Entries are the representation of cryptocurrency.
Cryptocurrencies are generated by the network in most cases to incentivize the peers, also known as nodes and miners, to work to secure the network and check entries. Each network has a unique way of generating them and distributing them to the peers.
Bitcoin, for example, rewards peers (known as miners on the Bitcoin network) for “solving the next block.” A block is a group or entries. The solving is finding a hash that connects the new block with the old one. This is where the term blockchaincame from. The block is the group of entries, and the chain is the hash. Hashes are a type of cryptologic puzzle. Think of them as Sudoku puzzles that the peers compete to connect the blocks.
Every cryptocurrency is a little different, but most of them share these basic characteristics:
How cryptocurrencies emerged as a side product of digital cash?
Few people know, but cryptocurrencies emerged as a side product of another invention. Satoshi Nakamoto, the unknown inventor of Bitcoin, the first and still most important cryptocurrency, never intended to invent a currency. In his announcement of Bitcoin in late 2008, Satoshi said he developed “A Peer-to-Peer Electronic Cash System.“ His goal was to invent something; many people failed to create before digital cash.
After seeing all the centralized attempts fail, Satoshi tried to build a digital cash system without a central entity. Like a Peer-to-Peer network for file sharing.
This decision became the birth of cryptocurrency. They are the missing piece Satoshi found to realize digital cash. The reason why is a bit technical and complex, but if you get it, you‘ll know more about cryptocurrencies than most people do. So, let‘s try to make it as easy as possible:
To realize digital cash you need a payment network with accounts, balances, and transaction. That‘s easy to understand. One major problem every payment network has to solve is to prevent the so-called double spending: to prevent that one entity spends the same amount twice. Usually, this is done by a central server who keeps record about the balances.
In a decentralized network, you don‘t have this server. So you need every single entity of the network to do this job. Every peer in the network needs to have a list with all transactions to check if future transactions are valid or an attempt to double spend.
But how can these entities keep a consensus about this records?
If the peers of the network disagree about only one single, minor balance, everything is broken. They need an absolute consensus. Usually, you take, again, a central authority to declare the correct state of balances. But how can you achieve consensus without a central authority?
Nobody did know until Satoshi emerged out of nowhere. In fact, nobody believed it was even possible.
Satoshi proved it was. His major innovation was to achieve consensus without a central authority. Cryptocurrencies are a part of this solution – the part that made the solution thrilling, fascinating and helped it to roll over the world.