A method and system include receiving, by a computer from an e-Commerce website, a payment authorization request that comprises payment data and a Mobile Station International Subscriber Directory Number (MSISDN) associated with a mobile device; verifying the MSISDN by comparing MSISDN to a subscriber database; generating a message to verify a payment transaction at the e-Commerce website, after the MSISDN is validated; receiving the verification message at the mobile device; verifying the payment transaction by transmitting a mobile personal identification number (PIN) associated with the MSISDN in response to the verification message; generating an authorization message indicating the payment transaction is one of approved or declined; and transmitting the authorization message to a merchant associated with the e-Commerce website. Numerous other aspects are provided.