This app was mentioned in 6 comments, with an average of 1.67 upvotes
I'll try to help you
If it's this app your files should be in /data/data/com.netqin.ps/files
Or in /sdcard/Android/data/com.netqin.ps/files
Vault
Vault for hiding images, videos and documents.
Found it!
https://play.google.com/store/apps/details?id=com.netqin.ps