One of the primary benefits of EMV is that it significantly reduces counterfeit fraud. This video from Paragon Application Systems Inc. explains how this is accomplished through the use of two online cryptograms:
An authorization request cryptogram, or ARQC, which is generated by the card;
An authorization response cryptogram, or ARPC, which is generated by the card issuer.
The video demonstrates how each of these is generated and validated to create a secure transaction.