If you are willing to export all of your blogspot blogger posts for security reason that's a very good idea! It is very easy to do so. Actually there is nothing easy than exporting blog post. (If you want to transfer your blogger blog posts to wordpress or blog.com you can export them directly, no need to download posts).
OK. I'm now showing you the procedure to export blogger posts.
Step 1: Log in to your blogger account.
Step 2: Click on Settings.
Step 3: Here you will find three options one by one like "Import Blog" "Export Blog" "Delete Blog". Click on Export Blog tab.
Step 4: Then a new page will appear with this "Download Blog". Click on it.
If you feel any problem you can ask me any question via comment.