The proof-of-stake is a method of securing a cryptocurrency network and achieving distributed consensus through requesting users to show ownership of a certain amount of currency. It is different from proof-of-work systems that run difficult hashing algorithms to validate electronic transactions. The scheme is largely dependent on the coin, and there's currently no standard form of it. Some cryptocurrencies use a combined proof-of-work/proof-of-stake scheme.[16]

Cryptocurrencies have been compared to Ponzi schemes, pyramid schemes[77] and economic bubbles,[78] such as housing market bubbles.[79] Howard Marks of Oaktree Capital Management stated in 2017 that digital currencies were "nothing but an unfounded fad (or perhaps even a pyramid scheme), based on a willingness to ascribe value to something that has little or none beyond what people will pay for it", and compared them to the tulip mania (1637), South Sea Bubble (1720), and dot-com bubble (1999).[80]
Needless to say, Bitcoin’s place as an alternative digital asset among cryptocurrencies has become entrenched, despite likely headwinds it will continue to face as it evolves further. The U.S. Securities and Exchange Commission (SEC) announced in early August 2017 that certain Initial Coin Offerings (ICOs) – which use cryptocurrencies for financing – would be regulated as securities.
Among the Asian countries, Japan is more forthcoming and regulations mandate the need for a special license from the Financial Services Authority to operate a cryptocurrency exchange.[24][25] China and Korea remain hostile, with China banning bitcoin miners and freezing bank accounts.[26][27] While Australia is yet to announce its conclusive regulations on cryptocurrency, it does require its citizens to disclose their digital assets for capitals gains tax.[28]
On 25 March 2014, the United States Internal Revenue Service (IRS) ruled that bitcoin will be treated as property for tax purposes. This means bitcoin will be subject to capital gains tax.[63] In a paper published by researchers from Oxford and Warwick, it was shown that bitcoin has some characteristics more like the precious metals market than traditional currencies, hence in agreement with the IRS decision even if based on different reasons.[64]
Cryptocurrencies allow traders to diversify their investment portfolio, as their price is mainly determined by demand and supply; Their value has a low correlation to national economies or political scenarios. Once Bitcoin surpassed the price of gold in 2017, US markets introduced 2 ETFs on Bitcoin and drew more and more institutional money into the world of cryptocurrencies. In 2017, Indian PM Narendra Modi has announced the gradual replacement of paper currency with electronic currency; In March 2018, the Marshall Islands announced that they would be introducing a cryptocurrency to replace US dollars as their main currency; other central banks are investigating the adoption of blockchain-like technologies… in short cryptocurrencies are probably here to stay. A growing number of crypto investors all over the world have already discovered the benefits:
In 1983, the American cryptographer David Chaum conceived an anonymous cryptographic electronic money called ecash.[7][8] Later, in 1995, he implemented it through Digicash,[9] an early form of cryptographic electronic payments which required user software in order to withdraw notes from a bank and designate specific encrypted keys before it can be sent to a recipient. This allowed the digital currency to be untraceable by the issuing bank, the government, or any third party.