An ODIN file is a file encrypted by the Locky Virus, a trojan horse created by cybercriminals that targets Windows users. It contains a user's file, such as a .WMV or .PDF file, encrypted with RSA algorithm and AES-256 encryption. ODIN files became prevalent in 2016 and are similar to .LOCKY files.

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 typically introduced through a file attached to a spam email. Once the virus affects your computer it begins scrambling your files, renaming them, and encrypting them. The virus then generates "_HOWDO_text.bmp", "_HOWDO_text.html", and "_[2_digit_number]_HOWDO_text.html" files that contain instructions informing you of the takeover and what you need to do to recover your files. NOTE: There is no program currently available to effectively restore files encrypted by the Locky Virus. If you back up your files you can execute a full system restore.