prevent multiple download

[hjvanes]

Dear PPL,

 

I was wondering to get some advice on how I can prevent multiple download of a trial software I have up on my website.

 

The idea is that the user should be able to download the trial software initially.  However, it should also recognise him/her coming back to the website in 10 days time or a month after the expiration to redownload it again.

 

I understand a method to use would be cookies, however these can be deleted or if using a different browsers can still allow the download to occur.

 

I need to be able to recognise the computer surfing the website in some fashion or another.  IP address is another method but even these can change and is in no way a secure method for detecting.

 

Not sure if there is a way to obtain the computer id.

 

Any help or pointers would be greatly appreciated and thank you in advance.

 

regards,

HJ

[requinix]

Don't give them direct access to the file. Instead make them go through a download script of sorts. That script checks the logged-in user and the download requested and can approve (and send the file) or reject (show/redirect to an error message) the request. In your case you'd log somewhere the first time the user requests a file, then next time look in the log and reject because they've already downloaded it.

[kicken]

The only way you can identify someone is to require them to register an account prior to downloading the software. Even this can be worked around by people just registering multiple accounts though.

 

There is no way without a registration process to accurately identify one person vs another person, so if you try you'll most likely only stop/annoy legitimate users while someone actually trying to abuse the trial would be more or less unaffected.

 

This is why most trial programs do not restrict the downloads but instead either contain some kind of code to lock the program after x number of days or have limited functionallity. Download the installer all you want, it'll only work for x days after the initial install or only with some restrictions.