A system and method provide efficient, secure, and highly reliable authentication for transaction processing and/or access control applications. A Personal Digital Key stores one or more profiles (e.g., a biometric profile) in a tamper-proof memory that is acquired in a secure trusted process. Biometric profiles comprise 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.