A “no key” message is frustrating, but it is also useful evidence. The right response is to preserve the files and understand what the decryptor is telling you—not to cycle through random universal decryptor downloads.
Why a decryptor reports no key
The tool may have identified a STOP/Djvu case but not possess the key required for those files. This is common with unique online-key infections.
New-variant messages
Modern STOP/Djvu variants changed the cryptographic situation compared with older releases. Some recovery techniques that worked for older variants do not apply to newer ones.
Do not keep rewriting the same encrypted files
Repeated experiments can make troubleshooting harder. Work on copies and preserve the originals in a stable archive.
What to record
- The exact decryptor message.
- The encrypted file extension.
- Any personal or offline ID shown by trusted tools.
- The ransom note filename and a copy of the note.
For the key concepts, read offline vs online keys.