A method and system is provided for generating a dynamic card value (DCV) from a mobile user device for use in a transaction between a user cardholder and a transaction provider. The DCV may be configured for use as a card verification value (CVV), also known as a card security code (CSC), a primary account number (PAN), or a portion of a PAN. The DCV may be generated using a DCV generator which may include an algorithm and a DCV generation key. The DCV generation key may be camouflaged. Obtaining a DCV from the user device may require inputting a PIN, a device identifier, a challenge or transaction information. The DCV may be used for any transaction requiring the input of a user identification number and a verification value, including, credit card transactions, debit card transactions, online or telephonic transactions.