Hidden files from SD card reduces phone memory

[patvish]

I am using HTC M8 and my issue is with hiding video files. For hiding video files I am using gallery vault app. The problem is that I have a video file (wmv format) 1 gb in size on my SD card and when I try to hide the file using gallery vault or any other video hiding app the video file reduces phone memory. I was told that when a file in SD card is encrypted it is getting stored in the same destination (SD card). For eg. a file in SD would remain in SD even after hiding. So why does the files which are hidden is reducing my phones memory. I had the same problem with my S4 phone.
Can anyone provide a solution to this Problem

 

[MADDROID]

Perhaps the encryption app is moving the file to main memory and doing the encryption there, then copying the encrypted file back to SD Card, BUT leaving the file in its cache also. Try emptying the cache and data of the app.