FOX-IT and FireEye have partnered together and have been able to recover the private keys used in the CryptoLocker encryption which locks users out of their own files. They have also been able to reverse engineer the devastating ransomware. As a result of their efforts infected users can go to their website, upload an encrypted file and have the necessary key used to decrypt the files emailed to them.
Users are advised to upload files that do not contain any personal or sensitive information, even though FOX-IT and FireEye are reputable companies.
You can read the Ars Technica write up on this here.
