Thanks for response.
Unfortunately, something is different in my experience when I mounted with BoxCryptor one folder stored in Google Drive volume and another folder stored in Synology NAS.
Let see the image, in the left side is the file encrypted on Synology drive and in the right side the same file crypted on Google Drive, also the original (unencrypted files is like in right side).
I try the experiment with one 1-byte length file also with one 10-byte long file, the result is the same.
In the Google Drive is stored with original size, in the Synology drive is rounded up to 16-byte.
(if the original file size equal or more than 16-byte and less than 32-byte, the file size is rounded to 32-byte)
About the encryption, below is the real size of encrypted files stored on Synology (left) and Google (right).
I think the purpose of BoxCryptor mounted volume could be to show the original file, not any modification because of encryption. This is realized in case if the encrypted files is stored on Google Drive. I don’t know why not in case when the encrypted files is stored on Synology NAS.