Portable App very slow decrypting

Using Portable App for Windows (v2.0) I’ve noticed, that decrypting large files is very very slow.

For example a single 58 GB file requires more than 1,5h to be decrypted.
This is much longer than encrypting same file at upload with native Windows Icedrive Desktop app.

It seems a really inperformant encryption/decryption mechanism is implemented there, maybe because Portable App is 2 years old now and requires some upgrade.

Any ideas how to improve performance there?