File encryption / decription in CodeIgniter

[eluser]WanWizard[/eluser]
You can also do it via cron in the background.

Have the files uploaded to a temporary location, and do not publish them directly after upload. Use a cron script to poll this directory, use GnuPG to encrypt them and store the encrypted versions in their final destination. Then start a piece of commandline PHP which updates the published state of the file, so it's available for download. Offcourse, for downloads the decryption has to be realtime. And that might be a factor too, your download request shouldn't timeout.

Any idea of the volume of uploads and downloads, lets say per hour? And the CPU specs and current load of this private server? I'm not afraid of memory (unless you're really short), but encryption/decryption can use lots of CPU. For that reason my Apache reverse proxies all use hardware offloaders for SSL.