my system infected a ransomware & encrypted all fiels as filename.koti
i have do backup infected files such as pictures and excel files
i have formated my pc to ger rid of ransomware
then used EMSISOFT DECRYPTOR FOR STOP dvju
"File: H:\phone backup\Android\data\com.zhiliaoapp.musically\cache\picture\fresco_cache\v2.ols100.1\6\2U6JaSd2VhHD2X1ya5h9v5rLg_w.cnt.koti
No key for New Variant offline ID: bQzou4YCQGWMhQnYUmmzNP6cr4msBmV2AwESnrt1
Notice: this ID appears be an offline ID, decryption MAY be possible in the future"