In a method for identity authentication, a portable electronic device displays a barcode encoding verification information for verifying authorization of access to the portable electronic device, and identification information for authenticating an identity of a user of the portable electronic device. An identification device scans the barcode and generates an authentication command. An authentication server extracts the verification information and identification information from the authentication command. When determined that the verification information is authentic, the authentication server authenticates the identification information and transmits a result to the identification device.