Malware Encryption

I had customer email me and he states that malware encrypted all his files with a .lucuuyk extension, I have looked everywhere to find what sort of ransomware may have done this but I can't find anything regarding this type of encryption. This is the email that a potential client sent me :

"Hi Gary,

I had a problem with a virus attack which has locked up a large number of files by adding the above extension to the file name. This means the file can no longer be opened. I worked with Symantec (Norton) to get the virus removed but this doesn’t unlock the affected files.

I do have a backup but it is up to 12 months behind the contamination event. Are you able to open up files which have the above added to them? (i.e. have a program that can reverse the lucuuyk encryption?

I will attach one file with the extension for you to look at.

Look forward to your reply in due course.

Richard Munro"

Any knowledge and help of this type of encryption would be appreciated.