The present invention relates generally to a smart card device that is configured to facilitate wireless network access and credential verification. Specifically, the device is configured to meet the physical and electrical specification for commercially available mobile devices utilizing a standard Subscriber Identity Module (SIM) for network access. The device combines the features of the SIM with Common Access Card or Personal Identity Verification card features to allow a network subscriber to invoke secure payment transactions over a carrier's network. The system includes data storage for maintaining a plurality of network and transaction instrument profiles and a profile gateway for receiving transaction information from a payment gateway, sending an authorization request to a user's mobile device, receiving a transaction authorization from the mobile device, and sending transaction information to a payment gateway to finalize the payment transaction.