A ZZZZZ file is a file encrypted by Locky ransomware, a virus utilized by cybercriminals. It contains a user's personal file, such as a .TXT or .PNG file, encrypted with AES-265 and RSA methods. ZZZZZ files became popular in 2016.

The Locky virus is highly dangerous malware. It is commonly referred to as ransomware, where the purpose of the virus is to take your files hostage and force you to pay the perpetrator (by way of bitcoin) to unlock your files. The virus is a trojan horse that is spread via spam email that include infected attachments or malicious links. Once the virus affects your computer it begins scrambling your files, renaming them, and encrypting them. The virus then generates a .TXT ransom note informing you of the takeover and what you need to do to recover your files. There is no program currently available to effectively restore your files. If you backup your files you can execute a full system restore. Otherwise, the only known way to decrypt your infected files is to pay the perpetrator for the private key and decrypt program.