How hard is it to use voice authentication?

Unlike speech recognition applications, which can be frustrating when they do not understand you, using voice recognition is very natural. The actual user interface depends on the application itself. For example, you might say your name into a smart phone application to unlock your phone. A bank could require a customer to repeat a passphrase before gaining phone-based access to their accounts. Voice biometrics can also passively analyze ongoing conversations to identify speakers in real time, without any extra effort on the speaker’s part.