Is there something like mod_secdownload (which is available for lighttpd) also available for Apache 2.x?
The mod provides expiring URLs, so that it is possible to prevent hotlinking of files. A similar feature is used by Amazon S3.
The server application has to generate a hash with a secret code and an expiry timestamp so that URLs only live for a given duration of time.
The closest thing I could find is mod_auth_token, but that seems to be Apache 1.3 only.