Payment system

A method of enhancing security of a payment application installed on a user device, the method comprising:

• receiving, by the user device via a communication network, a first session key different from an ICC Master Key from a remote entity, the first session key based on the ICC Master Key stored at the remote entity, the user device comprising a first processing portion and a second processing portion, the first processing portion comprising a first application environment within a secure element and the second processing portion comprising at least a second application environment, the second processing portion storing the payment application, and the payment application not storing the ICC Master Key on the user device, wherein the first session key is usable for a limited number of one or more transactions;
• in response to receiving the first session key, storing, by the second processing portion, the first session key;
• in response to storing the first session key, provisioning, by the second processing portion, the payment application with the first session key;
• receiving, by the user device via the communication network, a second session key from the remote entity, the second session key based on the ICC Master Key stored at the remote entity, the second session key being different from the first session key and the ICC Master Key;
• storing, by the second processing portion, the second session key;
• receiving, at the payment application, a request for an application cryptogram, wherein the request is from a point-of-sale terminal;
• and
• in response to the receiving, performing, by the payment application, an authorization process, wherein authorization process comprises:
• generating, by the payment application, the application cryptogram based on the received first session key;
• and
• transmitting, by the payment application, the generated application cryptogram to the point-of-sale terminal.