Flaw found in chip and pin
Chip and Pin credit and debit card readers can be tricked into accepting transactions without valid personal identification number.
That's according to new research by Cambridge University who say the system is fundamentally flawed and could open the door to fraud on a massive scale.
Experts came up with a trick test which fools the reader into thinking the correct numbers have been put in, by exploiting the way the reader talks to the shops terminal.
Professor Ross Anderson of Cambridge University says "We think this is one of the biggest flaws that has ever been uncovered against payment systems, and I've been in this business for 25 years."
However researchers have contacted banks about he loop[hole and said the programming skills to make a man-in-the-middle device to conduct the attack are relatively simple.