Free Secret Notes for Android.

LockNotes Features

password login (local password authentication)
note managements
find notes with specific words
storing notes encrypted
to change password
view mode : list view, card view, tile view
color selection
percent slider
to add a note from the shared text or link.
group management
private(secret) image management : store your image in the app's private storage and then get it when you need it.
export a note as a txt file.
short check-list.
export, import JSON
backup, restore : make a encrypted local backup and then restore to it if necessary.