Fast decrypton for various wav files async

I m trying to decrypt (Blowfish) a large ammount of wav files, which takes a lot of time.
Only some of these files are actually crucial, so, I was wondering if there s someway to decrypting the rest of the files asynchronously, while alowing the user to keep using the Plug in without having a large impact on the performance.

For what I been looking for, this kind of processing in a background tread would require too much memory, which would be a problem so i don´t really know if there´s a soltion.

Why should processing your data on a background thread require too much memory? Could you elaborate what kind of memory limitations you are expecting here? What you describe sounds like one of the most common examples on when to spin up background threads in the context of an audio plug in. Something like that is done by a lot of plug-ins out there

There s not any specific limitations. I been decrypting in the foreground, and the proccess increases the memory use quite a bit, thats why I thought it may have an negative impact in the performance of the rest of the plugin