The crypto locker virus an extortion style of virus to get you to pay a criminal entity cash in the hopes you can retrieve your files.

If you pay them your are gambling with someone who has already committed a criminal offense against you.

Quick tip if your infected: Get the virus off your system, then go to backups and view previous versions. This can be any formal backup saving your files with date revisions. You may also be able to use shadow copies of your files. Many of the cloud backup sites keep revisions too.

If your not infected try using one of the anti malware programs known to block this. Some are free others and commercial. Additionally make sure you have backups with multiple revisions. Backups and a lot of disk space are your friend here.

http://en.wikipedia.org/wiki/CryptoLocker

http://www.bleepingcomputer.com/virus-removal/cryptolocker-ransomware-information#ransom