Provided is a computer-implemented method for conducting a secure payment transaction for a purchase at a merchant using a client device and a remote point-of-sale (POS) system associated with the merchant. The method includes receiving, with a client device, at least one identifier for at least one product to be purchased, the at least one product associated with a transaction value, and detecting a checkout action with the client device. In response to detecting the checkout action, the method includes generating at least one transaction message based on the transaction value of the at least one item to be purchased and at least one account identifier, generating a cryptogram based at least partially on the at least one transaction message and the at least one issuer key, and transmitting the cryptogram to the remote POS system associated with the merchant. A system and computer program product are also disclosed.