A biometric authentication system is disclosed that provides authentication capability using biometric data in connection with a challenge for parties engaging in digital communications such as digital text-oriented, interactive digital communications. End-user systems may be coupled to devices that include biometric data capture devices such as retina scanners, fingerprint recorders, cameras, microphones, ear scanners, DNA profilers, etc., so that biometric data of a communicating party may be captured and used for authentication purposes.