A phenomenal growth in the number of credit card transactions, especially for on-line purchases, has also led to a substantial rise in fraudulent activities. Credit card fraudulent transactions are very easy to conduct, while very difficult to recover, compared to the fraud cases in hard-products transactions. In real life, fraudulent transactions could be interspersed with genuine transactions and simple pattern matching techniques are not often sufficient to detect the fraudulent transactions efficiently. Moreover, surrogate representations of identity can be easily forgotten, lost, guessed, stolen, or shared. Further it can be hacked through malicious websites or prone to security breaches.