Crypto-currencies are a subset of digital currencies, alternative currencies and virtual currencies. Crypto-currencies are also frequently called altcoins.
Created in 2009, Bitcoin was the first decentralized crypto-currency. Since then, many more crypto-currencies have been created with over 900 in existence as of mid 2017. Most of them are either similar to and/or derived from Bitcoin.
Most crypto-currencies have placed a cap on the total amount of currency that will ever be in circulation.
The legal status of crypto-currencies can vary significantly depending on the country: In some countries, crypto-currencies can be legally traded and used; in some other countries, their use is restricted or even banned.
Transactions made using crypto-currencies can be difficult to track since they are independent from the standard banking systems and in some cases can be anonymous. As a consequence, crypto-currencies have been used for tax evasion or money laundering.
CRIX, the CRyptocurrency IndeX has created a benchmark for the crypto market. As of September 2017, the CRIX consists of 9 crypto-currencies: Bitcoin, Ethereum, XRP (Ripple), LiteCoin, XEM, Dash, IOTA, XMR (Monero), and ETC (Ethereum Classic).