CLIENT DEVICE AUTHENTICATION USING CONTACTLESS LEGACY MAGNETIC STRIPE DATA

A technique for generating a diversified encryption key for a contactless legacy magnetic stripe card is disclosed. The diversified key can be generated using a master key, a key diversification value and an encryption algorithm. In one example embodiment, the key diversification value can be provided by the user as a fingerprint, numeric code or photo. The user can provide the key diversification value to the card or a cellphone. The card can generate the diversified key using the user provided key diversification value. The card or the cellphone can transmit the user provided diversification value to the server and the server can regenerate the diversified key using the user provided diversification value.