The weaknesses in MiFare are well documented and have been widely known for a number of years. Perhaps what is less well known are the specifics about some of the applications that are built upon these technologies and the way in which we can go about testing them. We have found through analysing a number of real world implementations that smart card systems are similar to web applications, they can be implemented really badly or implemented properly. In this talk we will give an introduction to MiFare for those not familiar and give an outline of the key weaknesses in the crypto contained in MiFare cards. We will then discuss a particular case study, run through the weaknesses in this particular implementation and the ways in which they can be leveraged to exploit the system. We will conclude by talking about the impact that NFC enabled mobile phones have on the security of these smart card systems.