In general, the techniques of this disclosure describe a computing device in a secure domain that is configured to receive, via a guard device, an authentication factor from a biometric authentication device in a non-secure domain. The biometric authentication device is in a non-secure domain, and the authentication factor comprises an identifier of a prospective user of the biometric authentication device. The computing device may then determine, based on the received authentication factor, whether the prospective user is a trusted user of the computing device based on the authentication factor. Responsive to determining that the prospective user of the biometric authentication device is the trusted user, the computing device may enable access to one or more applications on the computing device.
