I have my blog www.webspeaks.in which is on blogger (unfortunately I think). I provide files to be downloaded by my readers. I want that only the visitors who are subscribed to my blog can download the files. Is there any widget or tool available for this functionality.
I think Blogger doesn't support that but as a workaround you can try:
Upload documents online using google drive with security as "only people with link" and show link in a section of your blog that requires a visitor to be subscribed. They might still email link to their friends, but maybe is enough for you.