BOSTON -- Questions have arisen over the security of the Massachusetts Bay Transportation Authority's new CharlieCards after computer researchers discovered there may be a way hackers can find their way around the cards' encryption scheme.

University of Virginia researchers used only $1,000 worth of equipment to hack the cards and that means they may be vulnerable to thieves who could flood the streets with counterfeit cards, costing the MBTA thousands in revenues, the Boston Globe reported.

The company that manufactures the card's security chip said it features several layers of security and should be just fine.

The CharlieCard allows commuters to ride MBTA trains and buses after purchasing a set number of rides through ATM-style machines. Detectors then read a chip on the card that contains data about the user's account, and deducts the price of the ride.

The T spent close to $200 million on the CharlieCard system, which was introduced in 2006, replacing the use of money or tokens to buy rides.

The MBTA said it wouldn't comment on the report because it doesn't talk publicly about security issues.