When it comes to digital currency most people will think of Bitcoin.
But a different crypto-currency, Ether, is the hot pick on the online exchanges. In January 1 Ether cost about USD$8, but now it's worth about USD$90 ($130), a gain of 1125 percent in five months.
Ether is the online currency for a project called Ethereum, which is based on unhackable software called the Blockchain.
The Blockchain is made up of little bits of data, like a bank transfer, that are locked together with other blocks of data into one long chain.
That chain is then copied to thousands of computers around the world every 10 minutes, creating one massive decentralised database that so far no-one has been able to hack.
The Ethereum project is using that Blockchain software to create so-called "smart contracts" that can self-execute. It has the potential to cut out the middlemen like banks and lawyers in transactions, revolutionising major industries.
Blockchain technology is gaining momentum and digital currency investors are taking a bet on Ethereum and its currency Ether as being a major platform.
However, Ether has yet to replace Bitcoin as the crypto-currency king for investors. One Bitcoin is currently trading at USD$1,705.
According to the Bitcoin exchange Coindesk, US$10,000 invested in 2010 is now worth US$193 million.