In one embodiment, a biometric device includes a first portion having a processor and a second portion releasably coupled to the first portion. The processor is configured to determine whether the second portion is coupled to the first portion. The processor is configured to operate in an enrollment mode while the first portion is coupled to the second portion and operate in an authentication mode while the first portion is decoupled from the second portion. In one embodiment, a method of biometric authentication includes, first, coupling two portions of a biometric device to put it into an enrollment mode, collecting a biometric sample, and generating and storing a corresponding enrollment code; and second, decoupling the two portions of the biometric device, collecting a biometric sample, generating a corresponding access code, and granting or denying access to an asset based on comparison of the enrollment code and the access code.