Techniques for securing communications between fixed devices and mobile devices. A mobile device management server mediates communications between the fixed device and mobile device. The mobile device management server enrolls mobile devices and then assists with pairing the mobile devices to fixed devices in an out-of-band manner. This enrollment, coupled with out-of-band pairing, improves the speed and security of authenticating communication between fixed and mobile devices. If the mobile device has appropriate capabilities, the mobile device management server may request that the mobile device obtain and verify biometric data from a user prior to enrollment and performing authentication procedures.