WinRAR changed its encryption between RAR3 and RAR5, and split archives add another layer. The version decides how much work an unlock can realistically involve.
RAR5 is the modern format and is designed to resist guessing more strongly than RAR3. Older archives from the WinRAR 4.x era are usually more tractable. The header of the file states which one you have, and that single fact changes the realistic outlook more than any hint.
Recovery process
RAR5 is the modern format and is designed to resist guessing more strongly than RAR3. Older archives from the WinRAR 4.x era are usually more tractable. The header of the file states which one you have, and that single fact changes the realistic outlook more than any hint.
A RAR set split into .part1.rar, .part2.rar and so on is one logical archive. All parts are needed to verify a password, and re-creating or repairing a missing volume is a separate problem from unlocking. Collect every part before starting, and never re-download only the first one.
If the file names are visible, only the data is encrypted. If WinRAR asks for a password before it lists anything, the headers are encrypted too. Header-encrypted archives hide the contents, which removes some of the context clues you might otherwise use.
Note whether the file names are visible, roughly when the archive was made, the WinRAR version if known, and any partial memory of the password. That combination is what makes a targeted search meaningful instead of a blind one.
These details help with the first profile check.
The outlook depends on the actual encryption profile.
Common situations
If the file names are visible, only the data is encrypted. If WinRAR asks for a password before it lists anything, the headers are encrypted too. Header-encrypted archives hide the contents, which removes some of the context clues you might otherwise use.
Next step
Start with format detection and choose the appropriate path only after the file is identified.
