WHAT ARE CRYPTO CURRENCIES?

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.
The single most important part of Satoshi‘s invention was that he found a way to build a decentralized digital cash system. In the nineties, there have been many attempts to create digital money, but they all failed.
… after more than a decade of failed Trusted Third Party based systems (Digicash, etc), they see it as a lost cause. I hope they can make the distinction, that this is the first time I know of that we’re trying a non-trust based system. – Satoshi Nakamoto in an E-Mail to Dustin Trammell
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. This 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.
Cryptocurrencies like Bitcoin and Ethereum use a peer-to-peer decentralized system to conduct transactions. Since the entire process is online, there are fears that the transactions maybe volatile and hackable, so we need a signature so secure to do this, this leads to using a cryptography
Digital Signatures
One of the most important cryptographical tools that are used in cryptocurrency is the concept of signatures. What is a signature in real life and what are its properties? Imagine a paper that you have signed with your signature, what should a good signature do?
• It should provide verification. The signature should be able to verify that it is you who actually signed the paper.
• It should be non-forgeable. No one else should be able to forge and copy your signature.
• Non-repudiation. If you have signed something with your signature, then you should not be able to take it back or claim that someone else has done it instead of you.
In the real world, however, no matter how intricate the signature, there are always chances of forgery, and you cannot really verify signatures using simple visual aids, it is very inefficient and non-reliable.
Cryptography gives us a solution to this by means of “digital signatures” which is done via the use of “keys”.
Cryptography is a method of using advanced mathematical principles in storing and transmitting data in a particular form so that only those, for whom it is intended for, can read and process it.
Encryption is one of the most critical tools used in cryptography. It is a means by which a message can be made unreadable for an unintended reader and can be read only by the sender and the recipient.
A cryptocurrency like Bitcoin consists of a network of peers. Every peer has a record of the complete history of all transactions and thus of the balance of every account.
A transaction is a file that says, Dave gives X Bitcoin to Temi“ and is signed by Dave‘s private key. It‘s basic public key cryptography, nothing special at all. After signed, a transaction is broadcasted in the network, sent from one peer to every other peer. This is basic p2p-technology. Nothing special at all, again.
The transaction is known almost immediately by the whole network. But only after a specific amount of time it gets confirmed.
Confirmation is a critical concept in cryptocurrencies. You could say that cryptocurrencies are all about confirmation.
As long as a transaction is unconfirmed, it is pending and can be forged. When a transaction is confirmed, it is set in stone. It is no longer forgeable, it can‘t be reversed, it is part of an immutable record of historical transactions: of the so-called block chain.
Only miners can confirm transactions. This is their job in a cryptocurrency-network. They take transactions, stamp them as legit and spread them in the network. After a transaction is confirmed by a miner, every node has to add it to its database. It has become part of the blockchain.
For this job, the miners get rewarded with a token of the cryptocurrency.