A method and system for authorizing a secure transaction using a portable device is disclosed. The method includes an authorization process performed in real-time that includes two phases: an authentication phase and a transaction processing phase. In the authentication phase, a resource provider system may receive a cryptogram from a portable device and verify the cryptogram. Upon the resource provider system obtaining an authentication response indicator, the transaction processing phase may include the resource provider system generating and transmitting an authorization request message to a processing computer. The resource provider system may then receive an authorization response message from the processing computer including an authorization response indicator, which completes the authorization process.