The Free On-line Dictionary of Computing (19 January 2023):

CryptoLocker

    The best known example of the kind of malware known
   as ransomware.  CryptoLocker encrypts files on your computer
   and then demands that you send the malware operator money in order
   to have the files decrypted.

   According to FBI estimates, CryptoLocker had more than 500,000
   victims between September 2013 and May 2014.  Around 1.3 percent
   paid to free their files, earning the malware makers around $3
   million.  The criminal network was smashed by authorities and
   security researchers in May 2014 and a tool put online to decryt
   victim's files for free.


(http://thehackernews.com/2014/08/CryptoLocker-Decryption-Keys-Tool.html).

   (2015-01-22)