1 point@manjunath and @Baliitsolutions this is a newer variant of STOP/Djvu, and both of you have online ID's, which means that there is currently no way to recover your files. We recommend making a backup of any encrypted files and waiting, as it is possible that law enforcement may catch the criminals at some point and release their database of keys for use in decrypters. There is more information at the following link: https://support.emsisoft.com/topic/32045-about-the-stopdjvu-decrypter/
1 pointI have read the following article : Based on that article , I understand that we have to make an encrypted backup on a CLOUD storage driver for our safety. Then , we have to wait for new solutions and updates for removing and decrypting the .derp files.