From Centralization to Decentralization
The major drawback of the traditional fiat currency payment system is high transaction fees with a long settlement period, which has led people to alternative currencies that allow for shorter peer-to-peer (P2P) processing time without intermediaries, resulting in a thriving market for digital currencies that have lower settlement risk. Prior to the creation of cryptocurrencies, there were many other types of digital currencies. The most common example is a digital currency created by an institution and transacted on a platform. Such currencies can be loyalty points created by companies or digital coins created by Internet-based platforms. The institutions or legal entities control the creation, transaction, bookkeeping, and verification of the digital currencies. In other words, these platform-based digital currencies are centralized. A notable example is the loyalty points of e-commerce companies like Rakuten and iHerb, which function like cash on the platform. Q-coin, introduced by the Chinese social platform Tencent, can be bought using the Renminbi and can be used to buy services at Tencent. World of Warcraft Gold is a game token that can only be earned through completing in-game activities and cannot be bought or exchanged into fiat currencies .
These centralized digital currencies are transacted within a specific platform and are designed to support the business of the issuing institutions. It is difficult to use them as a substitute for fiat money because these centralized digital currencies are not legal tender. Therefore, decentralized digital currencies seem a potential replacement for fiat money as no central authority is needed to verify the transactions. However, there are still many obstacles to overcome without the use of an intermediary or central authority. One main obstacle is the double-spending problem: It is possible to spend the same digital coin more than once. This problem has remained unsolved for a long time, discouraging the prevalence of decentralized coins. To ensure every transaction is accurately reflected in the account balance for digital currencies to prevent double spending, there is a need for a trusted ledger without a central authority.
The first cryptocurrency, eCash, was a centralized system owned by DigiCash, Inc. and later eCash Technologies. Although it was phased out in the late 1990s, the cryptographic protocols it employed avoided double spending. A blind signature was used to protect the privacy of users and served as a good inspiration for subsequent development. Shortly after the discovery of cryptography protocols, digital gold currency became popular, among which the most used was e-Gold. It was the first successful online micropayment system and led to many innovations, making transactions more accessible and more secure. However, the failure to address compliance issues finally resulted in its liquidation in 2008, despite an annual transaction volume of over US$2 billion .
The global financial crisis in 2008, coupled with a lack of confidence in the financial system, provoked considerable interest in cryptocurrency. A ground-breaking white paper by Satoshi Nakamoto was circulated online in 2008. In the paper, this pseudonymous person, or persons, introduced a digital currency that is now widely known as bitcoin. Bitcoin uses blockchain as the public ledger for all transactions and a scheme called PoW to avoid the need for a trusted authority or central server to timestamp transactions . Because blockchain is an open and distributed ledger that records all transactions in a verifiable and permanent way, it solves the double-spending problem.
Bitcoin and “bitcoin”
The cryptocurrency, denoted by bitcoin or BTC, can be accepted as a payment for goods and services or bought either from other people or directly from exchanges/vending machines. These bitcoins can be transacted via software, apps, or various online platforms that provide wallets. Another way to obtain bitcoin is through mining.
The Bitcoin system runs on a P2P network, and transactions happen directly between users with no intermediary. Bitcoin decentralizes the responsibilities of verifying the validity of transactions to the entire network. Transactions are recorded in the public ledger called blockchain and are verified by network nodes, which could be any individual using a computer system with Bitcoin software installed. Once users have made a transfer, the transaction will be broadcast between users and confirmed by the network. Upon verification, it will be recorded in the blockchain, and then the transfer is completed. This record-keeping process is referred to as mining, and people offering the computing power to do so are called miners. Bitcoins are created as an incentive for solving the cryptography puzzle using transaction data; thus, successful miners are rewarded with the newly created bitcoins, on top of transaction fees.
Each transaction contains inputs and outputs. An input has the reference to the output from the previous transaction, and the output of a transaction holds the receiving address and the corresponding amount . In general, in a transaction, a certain number of bitcoins is sent from a bitcoin wallet to a specific address, if there is a sufficient bitcoin balance in the wallet from previous transactions. Transactions are not encrypted and can be viewed in the blockchain with corresponding bitcoin addresses, but the identity of the sender or receiver remains anonymous. Typically, bitcoin wallets have a private key or seed that is used to sign transactions. This secured piece of data provides a mathematical proof that the coins in the transaction come from the owner of the wallet. With the private key and the signature, the account can only be accessed by the owner, and transactions cannot be altered by someone else.
Mining is also the process of adding newly verified transaction records to Bitcoin’s public ledger. The records are grouped and stored in blocks. Each block contains a timestamp and a link to a previous block so that the blocks are chained together, thus the name blockchain. The blocks are mined in sequence, and once recorded, the data cannot be altered retroactively. A complete record of transactions can be found on the main chain. Each block on the chain is linked to the previous one and can be traced all the way back to the very first block, which is called the genesis block. However, there are also blocks that are not part of the main chain, called detached or orphanedblocks. They can occur when more than one miner produces blocks at similar times, or they can be caused by attackers’ attempt to reverse transactions. When separate blocks are validated concurrently, the algorithm will help maintain the main chain by selecting the block with the highest value.
There are several systems by which miners can earn rewards through the mining process. Bitcoin uses the Hashcash PoW system and the SHA-256 hashing algorithm. Under the PoW system, rewards are given according to the number of blocks that are mined successfully. Therefore, mining is quite competitive; the miner who first solves a given puzzle or gets the highest value will take all the newly created bitcoins, and the other miners will receive nothing. Rewards thus encourage miners to take an active part in mining data blocks. In addition, mining usually involves a large amount of computation and can be quite energy consuming.
Another commonly seen system is proof-of-stake (PoS). Unlike PoW, no additional work is required under the PoS scheme because investors are rewarded based on the number of coins they hold. For example, a user holding 1% of the currency has a probability of mining 1% of that currency’s PoS blocks . In general, this system does not require a large amount of work for the computation. It provides for higher currency security and is usually used in combination with other systems, as in the case of Peercoin, the first cryptocurrency launched using PoS.
Because the supply of bitcoins is limited to 21 million, the bitcoins awarded to a miner for successfully adding a block will be halved every 210,000 blocks (approximately every four years), according to the Bitcoin protocol. When Bitcoin was first run in 2009, the reward amounted to 50 newly created bitcoins per block added to the blockchain, but the reward has been halved twice to 12.5 as of July 9, 2016. The supply of bitcoins on the network is 16.907 million as of March 6, 2018, with a total circulating supply market capitalization of US$ 159.1 billion.3
Features of Bitcoin
Decentralized. Similar to conventional currencies that are traded digitally, bitcoin can also be used to buy things electronically. Unlike any fiat money or platform-based digital currencies, however, bitcoin is decentralized. In other words, there is no single group or institution that controls the Bitcoin network. Its supply is governed by an algorithm, and anyone can have access to it via the Internet.
Flexible. Bitcoin wallets or addresses can be easily set up online without any fees or regulations. Furthermore, transactions are not location specific, so bitcoins can be transferred among different countries seamlessly.
Transparent. Every transaction will be broadcast to the entire network. Mining nodes or miners will validate the transactions, record them in the block they are creating, and broadcast the completed block to other nodes. Records of all transactions are stored in the blockchain, which is open and distributed, so every miner has a copy and can verify them.
Fast. Transactions are broadcast within a few seconds, and it takes about 10 minutes for the transaction to be verified by miners. Thus, one can transfer bitcoins anywhere in the world, and the transactions will usually be completed minutes later.
Low transaction fees. No transaction fee is required to make a transfer historically, but the owner can opt to pay extra to facilitate a faster transaction. Currently, low priority for mining transactions (a function of input age and size) is mostly used as an indicator for spam transactions, and almost all miners expect every transaction to include a fee. Miners historically have been incentivized mainly by newly created coins, but that is changing. As the number of bitcoins in circulation nears its limit, transaction fees will eventually be the incentive for miners to carry out the costly verification process.
Bitcoin is open source and the source code is available on GitHub.4 Therefore, coders around the world have been enlightened by the invention of Bitcoin and have created hundreds of cryptocurrencies, which are referred to as alternative cryptocurrencies, or altcoins. Bitcoin is not perfect. Every new purpose or pain point is an incentive to invent new coins. Coins are invented to address specific issues such as high computation cost of PoW, to increase the number of transactions per second, to increase the block size, to ensure that the ledger is not as transparent, to accommodate more efficient use of smart contracts, and so on. Moreover, to pay for development and launch expenses, developers can raise funds for the project even before the cryptocurrency is launched. In particular, initial coin offerings (ICOs), initial crypto-token offerings, and initial token sales are similar approaches to raising funding to develop new crypto-tokens and cryptocurrencies. ICOs allow people to invest in a project by buying part of its cryptocurrency tokens or prelaunched ERC20-compliant tokens residing on the Ethereum network in advance, typically based on a white paper or other documents on the project for investors to evaluate.
As of October 6, 2017, 869 cryptocurrencies and 269 crypto-tokens were launched and traded,5with a total market capitalization of over US$148.4 billion. Different from fiat money, cryptocurrencies have a circulating supply, total supply, and maximum supply. Maximum supply refers to the best approximation of the maximum amount of coins that will ever be created in the lifetime of the cryptocurrency, and total supply is the total number of coins existing at the present moment. However, some coins will have been burned, locked, or reserved or cannot be traded on the public market, so the circulating supply is computed by deducting those coins from the total supply. When determining the market capitalization, circulating supply is used because it denotes the amount of coins circulating in the market and accessible to the public.
Based on cryptocurrency market value as of June 27, 2017, Bitcoin dominated the market with more than half of the total market value and the highest price. Ethereum, Ripple, and Litecoin also have large market capitalizations of more than US$1 billion. In addition, the supply of different coins varies substantially due to the unique characteristics of each coin, and some coins are not mined, suggesting a fixed amount of supply. The price of the coins ranges from US$0.002 to well over US$1,000.
In general, some altcoins are very similar to bitcoins, whereas others are created by adopting very different methods or ideas. Market capitalization, different categories of altcoins, .
Appcoins, such as MaidSafeCoin, function like digital shares in a decentralized autonomous organization and are sold in token sales for a portion of future profits. Most altcoins are direct copies of Bitcoin, with some minor changes in parameters such as block-generating time and the maximum limit of coin supply. However, many altcoins have adopted other innovative changes. Among the widely accepted altcoins, Ethereum is the one with the most innovative ideas and widely followed besides Bitcoin. The value token of the Ethereum blockchain is called ether and denoted by XRP. It provides a decentralized Turing-complete virtual machine that features smart contract functionality, as do four other altcoins that have launched based on Ethereum: Ethereum Classic, Golem, Augur, and Gnosis. NEM falls under the third category in (i.e., coins coded in a different programing language): It is operated using JAVA programming, as is Nxt. Stellar Lumens and Factom are excluded because they are based on Ripple and Bitcoin protocols, respectively.
To conclude, many cryptocurrencies other than bitcoin are traded actively with a wide assortment of features for investors to invest in. The complet coins list with over 1300 cryptocurrency , tokens and altcoins on https://cryptocoinhubs.com