In 2008, following the bankruptcy of Lehman Brothers, the venerable Reserve Primary Fund broke the buck: It held millions of Lehman's debt obligations, and panicked redemptions by its investors caused its NAV to fall to 97 cents per share. The pullout of money caused the Reserve Primary Fund to close and triggered mayhem throughout the money markets.
Paul Krugman, Nobel Memorial Prize in Economic Sciences winner does not like bitcoin, has repeated numerous times that it is a bubble that will not last and links it to Tulip mania. American business magnate Warren Buffett thinks that cryptocurrency will come to a bad ending. In October 2017, BlackRock CEO Laurence D. Fink called bitcoin an 'index of money laundering'. "Bitcoin just shows you how much demand for money laundering there is in the world," he said.
There are also purely technical elements to consider. For example, technological advancement in cryptocurrencies such as bitcoin result in high up-front costs to miners in the form of specialized hardware and software. Cryptocurrency transactions are normally irreversible after a number of blocks confirm the transaction. Additionally, cryptocurrency private keys can be permanently lost from local storage due to malware, data loss or the destruction of the physical media. This prevents the cryptocurrency from being spent, resulting in its effective removal from the markets.
The first decentralized cryptocurrency, bitcoin, was created in 2009 by pseudonymous developer Satoshi Nakamoto. It used SHA-256, a cryptographic hash function, as its proof-of-work scheme. In April 2011, Namecoin was created as an attempt at forming a decentralized DNS, which would make internet censorship very difficult. Soon after, in October 2011, Litecoin was released. It was the first successful cryptocurrency to use scrypt as its hash function instead of SHA-256. Another notable cryptocurrency, Peercoin was the first to use a proof-of-work/proof-of-stake hybrid.