A card reader for use in web based transactions is provided. In one embodiment, the invention relates to a method for establishing a secure connection between a card reader and a server, the method including receiving a first challenge request, generating a response to the first challenge request using a first encryption key, sending the response to the first challenge request, sending a second challenge request, receiving an encrypted response to the second challenge request, verifying the encrypted response to the second challenge request; and, if the encrypted response is verified, reading data card information from a data card, the data card information including an intrinsic magnetic characteristic and recorded data on the data card, generating a magnetic fingerprint based on the intrinsic magnetic characteristic, and sending the magnetic fingerprint to authenticate the data card.