TypingDNA [1] recognises people by the way they type, and provides typing biometrics (aka keystroke dynamics) as a service via an API. This is currently used for Multi-Factor Authentication in industries like Banking and Education [2].
Don't take my word for granted, see it with your own eyes and even try it with a friend (can somebody else replicate your typing pattern?) [3]
There are free accounts provided to developers, so you can easily call the API yourself [4]
Thank you for sharing this, very interesting! Although a bit old (2015), the article raises some questions on privacy & transparency, which are more important than ever (eg: the increasing legislation like GDPR, CCPA).
Luckily, the TypingDNA solution is secure and compliant, in accordance not only to the Privacy laws (GDPR, CCPA), but also to other kind of legislation like Strong Customer Authentication (SCA) required by the EU Payment Services Directive (PSD2)