Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data: Rugj also generates a ransom note, the ' _readme.txt' file. For example, it renames ' 1.jpg' file to ' 1.jpg.rugj', ' 2.jpg' file to ' 2.jpg.rugj', and so on. This variant encrypts files and appends the '. Rugj ransomware belongs to a family of ransomware called Djvu.