Abstract: A system and computer-implemented method for protecting against fraud by authenticating communications and communicative devices in real time and prior to accepting instructions or otherwise substantively engaging via the devices. A software app on the mobile phone of a cardholder creates a token, which is also provided to a card issuer. Historical authentication information is collected about the mobile phone and an associated cardholder. An authentication request, including the token, is received from the card issuer when communication is initiated by the mobile device. Current authentication information is also collected. The historical and current authentication information is analyzed, an authentication result is generated reflecting a likelihood that the mobile phone is being legitimately used by the cardholder associated with it, and the authentication result is communicated to the card issuer.