Even though the installation prompts you for an optional password to access your recordings, it only secures the audio files IF you're attempting to explore them via the Boldbeast software. You can easily circumvent the password requirement by using programs such as File Explorer (even Windows Explorer!!). You will find all the audio recordings unencrypted in the BBRec directory. I found this to be so with Galaxy S6 Edge, Sony Experia Z2, Xperia M2, Galaxy S4 Mini among other Droids. Mind you, these were not installed with any bootleg boldbeast software. I purchased them. So, why do I continue on with Boldbeast being aware of this vulnerability? Because it records v. clearly and has several tweaks to suit my needs . But if your mobile falls into unscrupulous hands ..... The developers should secure this loophole.
Most users want to save recorded files into the sd card, as a result all apps can visit the files.
If you want to hide the files from all other apps, please change the "Clip Saving Folder" option in Boldbeast Recorder to this folder:
/data/data/com.boldbeast.recorder/files/BBRec
Now you get what you want.
NOTE
if you uninstall Boldbeast Recorder the built-in application manager will delete all your recorded files. However if you save files to the sd card they'll not be deleted by the application manager. So please make your decision with caution.