I am new to Trusty TEE OS. Is there any way to find out if an Android Device uses such an OS without rooting the device ?
AFAIK there, DRM (Digital Rights Management) is the most widely used application of Trusty OS. Some examples for DRM frameworks are Widevine/PlayReady/ClearKey.
Does it mean that if any of these frameworks are present in the Android device, it is safe to assume that there is an underlying Trusty TEE OS in use ?
Thanks
Both Widevine and PlayReady support multiple security levels - the most secure level for each is tied to the TEE but lower levels are typically not.
Hence, a simple check for DRM will not tell you if the device has TEE.
On older versions of Widevine you would determine the security level fairly easily which would give you a guide - I don't think you could take it as absolute:
The same approach does not work for the current version of Widevine.
I don't believe there is a simple 'TEE supported' API - there are some tricks to try to determine - see the discussion in this answer: https://stackoverflow.com/a/64422042/334402