As we prepare to try and pay off what we've spent on debit and credit card bills in the run up to Christmas it's worth checking that all the items on the statement are for things we've actually bought.
Although the banking industry insists the introduction of chip and pin has dramatically reduced card fraud, experts believe criminals are getting better at cheating the system.
When we looked at some of the possible weaknesses in chip and pin security at the end of last year we got a big response from listeners. So we sent Bob Howard to visit Steven Murdoch, an expert in Chip and Pin fraud at the Cambridge Computer Lab, to put some of your theories to the test.
This item was first broadcast on Radio 4's Money Box on Saturday, 2 January 2010.