I am looking for a encrypted app for the android to keep sensitive documents in for work and personal records. So far I found a app called Protectstar TimeLock. The whole "hidden" aspect is gimicky but its the best that I can find because of ease of use. I like this one because you can access the items with out manually decrypting or reencrypting them after your done. If you want to view the files out side of the app you can "download" the files to your phone. https://www.protectstar.com/en/products/time-lock
It appears not to upload to a cloud, I dont want cloud upload.... But I dont have a way to verify that the files are truly 256 encrypted and my files are staying secure and no 3rd party can access them.
Cell phone gurus chime in, Running a encrypted Galaxy S5.