The security of a radio system hinges on its ability to effectively authenticate a user. This work proposes a two-factor authentication scheme using a token and a biometric. The users' access rights are determined during authentication and the users are served only those channels of data that they are privileged to receive. The strengths and the weaknesses of the implementation in reconfigurable hardware are identified. The capabilities of the scheme are put into perspective by comparing it to a high-end authentication system and by evaluating the use of standardized APIs and low-end authentication devices. Modifications to the system are suggested to improve the level of security the scheme provides. Finally, a baseline study is carried out to measure the data processing performance of a radio developed in reconfigurable hardware, which uses the proposed authentication scheme.