Is it possible to add a password to an existing zipfile with 7zip without going to all the trouble of unpacking it and re-packing it again?
You can password-protect an existing ZIP file with zipcloak.
EDIT: T. Furukawa crafted a patch for zipcloak that adds a password option, so batch processing is much easier:
C:\>for %f in (*.zip) do zipcloak -p password %f.
If you prefer a GUI, both WinRAR and PeaZip can batch encrypt existing archives.
In WinRAR: Select ZIP files > Tools > Convert archives > Compression... > Set password...
In PeaZip: Select ZIP files > Convert > Enter password / keyfile (optionally set algorithm to ZipCrypto under the Advanced tab for compatibility with Windows' built-in ZIP handling)
Yes, you can do it with 7-Zip, following below steps without doing any extract and repacking
- Right click files you want to add to zip
- 7-Zip -> Add to archive...
- New window opens with default name for new zip file.
- Next to that drop down box, there is a square button with three dots over it (Browse)
- Select existing zip file into which you want to add files
- Over already open window, Right-Bottom there is 'Encryption' block, with text boxes to input intended password, give inputs there
- Click OK