[web2py] any idea how hide downloads

[pandaluv]

i have something like this

def download():
    download_id = request.args(0)
    download = db.post(download_id)

    if str(download) == "None":
        redirect(URL(r=request,c="home",f="index"))

    form = FORM("Download: " + str(download_id) ,INPUT(_type='submit',
_value="Download"))
    form.insert(1,captcha)

    if form.accepts(request.vars, session):
           return redirect(URL(r=request,c='default',f='download/db',
args=download.file))
    elif form.errors:
        response.flash = T("Houston we have a problem")
    return dict(form=form)

then this redirects to

def download():
    return response.download(request,db)

and i get something like this

http://127.0.0.1:8000/init/default/download/db/post.file.998824c8547a4dd4.313239333035323337373332312e6a7067.jpg

catpcha fail in this case, i will be able to download from this URL

any idea how can i hide the downloads?  =D