Check the file signature (magic bytes). A standard RAR file starts with the hex string 52 61 72 21 ( Rar! ). 2. Archive Inspection
If you cannot see the names of the files inside without a password, the archive uses "header encryption." 7uuu4f1a6751c.rar
"Store" (no compression) can sometimes indicate that the file itself contains another hidden layer or is a disk image. 3. Password Recovery (If Locked) Check the file signature (magic bytes)