Pi is the first digital currency you can mine on your phone. You can mine for free without draining your battery by just confirming to mine every 24hours. Pi is being developed by a group of stanford PhDs, and at the moment has more than 3.5 milllion users mining on their phones in over 120 countries, and had just released a node software to even mine on your computer.
you can join Pi by copying this link: https://minepi.com/mksdznk and using my invitation code: mksdznk