I own an ecommerce platform that sells large (500 megabyte+) ebooks. To reduce server costs I am looking at hosting the ebooks on S3 and using Sendowl/ FetchApp to create the links to the downloads.
My understanding is that "customer buys ebook" -> "customer receives signed url (i.e. example.com/ksljfasdkfj
)" -> signed URL goes to actual s3 file (i.e. amazon.bucket/file1.pdf
)"
Assuming that the middleman I use to sign the domain works correctly, and my bucket file has the correct security settings, is this secure? What is keeping someone from just brute-forcing the file system to find other files or use the link after it expires? My nightmare would be a security hole wherein someone could access all the documents.