I know of one business that was recently affected by an infection of this particular malware. Unfortunately they did not have backups they could use to rebuild the affected systems (the malware also encrypts drives/shares on network devices that the affected system is connected to).Payment for the required key is made using Bitcoin.
Three tips/bits of advice for anyone worried ...
a) Get good anti-virus software on your Windows PC that can detect or can deal with this threat (the software is very good at avoiding AV software by having two required parts, the first is the email attachment the second is downloaded once the attachment is opened, the current strategy that software uses to prevent a Cryptolock attack is to block access to the internet servers that supply the second part of the infection)
b) The internet is a very bad neighbourhood; remember the advice from your mother ... never accept sweets from strangers. In the online world, don't open emails from strangers that look suspicious or if they are from known sources appear out of character from the norm. Immediately delete any suspicious mails.
c) Have good backups of your critical data along with the copies of the re-installation software for your PC. That way, if a) and b) fail you can wipe and rebuild your PC without any data loss (and remember the golden rule of backups ... test them, they're not backups unless you can get the data back).
JAS