How to secure my data?

I offer a bunch of clients back of their cPanel account. This is done by using FTP - they transfer the backups to an unique FTP account on my server, using the built-in backup function.

However, all those backups are stored unencrypted.

I paid a guy to make a php script that encrypt/decrypt backups开发者_StackOverflow社区, but it takes 5-7 minutes to encrypt 20MB of data - which I find too long time.

Any suggestions how to speed up the encryption, or am I doing it all wrong?

FTP is insecure. Consider using something like SCP. If you're on a Linux server there are many strong encryption tools available.

I'd recommend using the SFTP protocol for secure uploads instead of FTP.

Furthermore you could use phpseclib's class Crypt_AES to encrypt the uploaded files, which in my experience is one of the fastest pure PHP encryptions I've ever seen (around 1.5 minutes per 10 MB on a 2 GHz AMD, iirc. Heavily depends on your hardware, of course).