Apple has been granted a patent (number 10,225,252) for “dynamic watch-based CAPTCHA” that would improve security on an Apple Watch.
A CAPTCHA (completely automated public Turing test) is a type of challenge–response test used in computing to determine whether or not the user is human. One use of CAPTCHAs is to prevent automated programs ("bots") from accessing various types of computing resources or services. Illustrative uses include: prevention of comment spam in blogs; protection against automated email account registration and collection; prevention against the automated access and participation in online polls; prevention of automated dictionary attacks against password systems; prevention of automated search engine bots from indexing web pages; and the prevention of automated access to, and download of, data (e.g., from an online database).
Here’s Apple’s summary of the invention: “Techniques are disclosed for implementing a CAPTCHA access control system based on graphical representations of a watch or other timekeeping device. More particularly, the disclosed CAPTCHA system's request/challenge mechanism employs a graphical representation of a watch whose perturbation from a baseline visual presentation is controlled by a large number of attributes, each of which may assume a number of different values.
“The use of a large number of display attributes (e.g., 20 or more) and a relatively small number of difficulty levels allows each difficulty level to have an enormous number of possible graphical representation. Such a large number of potential challenge images essentially precludes the likelihood that any automated search for a matching image--providing the ability to correctly respond with certainty to the challenge query--will be successful.”
Of course, Apple files for — and is granted — lots of patents by the U.S. Patent & Trademark Office. Many are for inventions that never see the light of day. However, you never can tell which ones will materialize in a real product.