I need to securely download a file over https without using authentication.
The reason I need to do this is I want to create a zap at Zapier.com that allows me the copy a file from a https post to my Dropbox account. Currently their system only allows the URL of the file to be in a post field, not the actual file. I also can't provide authentication details, just a URL where the file is located.
I plan to store the file on Amazon S3 with a 32 character filename that is randomly generated. The way I see it, is having a complicated URL is similar to providing a username and password.
My question is, if I make it a very complication URL name and only make the file available for an hour or so, what are the odds of somebody just guessing the URL and downloading the file?
Does anybody have another suggestion how I can make it more secure? Ideas I have is only allowing IPs where Zapier is located or removed the file as soon as it is downloaded once, but I'm not sure if this will be very hard to implement straight on S3?