The '_readme.txt' file is a ransom note created to inform victims that all their files have been encrypted and provide contact and payment information. Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

Instructions on how to contact the attackers and other details are provided in the ' _readme.txt' file. rigd' extension to their filenames (for example, it changes ' 1.jpg' to ' 1.jpg.rigd', ' 2.jpg' to ' 2.jpg.rigd'). This variant encrypts files and appends the '. Rigd is part of the Djvu ransomware family.