PHILADELPHIA (KYW Newsradio) — Looking for a place to make trades in bitcoins? You'll find one in the Bourse in Old City. You'll find another at Spread Bagelry in University City.

In fact, there are about 100 of them across Philadelphia — bitcoin ATMs.

Bitcoin is what is called a cryptocurrency. "It's an electronic form of mobile transacting that can be done online without the use of a third party," explained Sean Keefe, managing partner of Straight Up Capital, based in Philadelphia.

If you've never noticed a bitcoin ATM, you aren't alone.

"They're almost hidden in plain sight, because they already are in Rittenhouse Square, South Philly, Queen Villiage," said Keefe.

Bitcoin ATMs aren't just in Philly's bigger neighborhoods either.

"There are also a lot of Bitcoin ATMs in some of the impoverished communities," added Keefe. "They're there actually for social good, to help provide access for the unbanked communities."

A bitcoin ATM "is very much like a regular ATM," said Keefe.

That's because some these ATMs allow you to take out cash by selling your bitcoin. They can also be used to purchase bitcoins.

"So you would go to the ATM, put in your information. They normally accept cash," said Keefe. "And then they would give you the option to either store on your exisiting bitcoin wallet, or if you don't have an exisiting bitcoin wallet, they would set one up for you."

He said it's good to see all these bitcoin ATMs popping up in Philadelphia, because he expects more and more places throughout the city will be accepting Bitcoin as a form of payment in the near future, on top of the many places that already do.