A system and method provide efficient, secure and highly reliable authentication for transaction processing and/or access control applications in which only biometric input is required from the user. A Personal Digital Key stores a biometric profile that comprises a representation of physical or behavioral characteristics that are uniquely associated with an individual that owns and carries the PDK. The PDK wirelessly transmits the biometric profile over a secure wireless transaction to a Reader for use in a biometric authentication process. The Reader compares the received biometric profile to a biometric input acquired at the point of transaction in order to determine if the transaction should be authorized.