Globally, cryptocurrencies are a subset of some alternative digital known currencies. A cryptocurrency exchange methods are using cryptography due to secure all transactions and to control the creation of new units. As far as Bitcoin became the first and more strong decentralized cryptocurrency in 2009 and, since then, due to large number of cryptocurrencies are being created trying to copy bitcoin success and, so on, have been created. These are frequently called as altcoins generally, because they are an alternative to Bitcoin (altcoin), for example, Dogecoin. Cryptocurrencies use decentralized control exactly as Bitcoin.
Bitcoin as a form of payment for products and services has seen growth, and merchants have an incentive to accept the digital currency because fees are lower than the 2-3% typically imposed by banks and credit card processors. Despite The European Banking Authority has warned that bitcoin lacks consumer protections, and, unlike credit cards, any fees are paid by the purchaser not the vendor. Bitcoins can be stolen and chargebacks are impossible. Commercial use of Bitcoin is currently small compared to its use by speculators and buyers, which has fueled price volatility last months. Bitcoin has been a subject of scrutiny amid concerns that it can be used for illegal activities. In October 2013 the US FBI shut down the Silk Road online black market and seized 144,000 bitcoins worth US$28.5 million (value at the time). Despite that, the US government is considered Bitcoin-friendly compared to other governments, for example, In China, buying bitcoins with yuan is subject to some restrictions, and bitcoin exchangers are not allowed to hold bank accounts.