Using Encryption

Decrypting files

The correct password is required before WinZip^® can unzip an encrypted file from a WinZip file. If WinZip does not already know the correct password from a previous operation during the same session on the same archive, it will ask you for the password when it is needed.

Note that WinZip unzips files not only for the Unzip operation but also when you view or open a file and when you use features such as Test, Unzip and Try, and Install. To enhance the security of your encrypted Zip files, when WinZip is done with the temporarily unzipped files, it will wipe the files prior to deleting them. This will prevent any unauthorized people from being able to recover these temporary files.

Encrypting files

You can encrypt files while they are being added, or you can encrypt (or re-encrypt) all files already in a Zip file (.zip or .zipx).

Encrypting files while adding

The most efficient way to encrypt files is to do so while you are adding them to an archive. In the WinZip Ribbon interface, click the Encrypt icon on the Zip tab of the WinZip ribbon BEFORE adding files to the Zip file. WinZip will then display the Encrypt dialog during the Add operation, where you will specify the password.

Tip: you can set a preferred encryption method from the Encryption section of the WinZip Settings dialog, accessible from the File tab of WinZip's ribbon.

When you add files to a Zip file from Windows Explorer, you will have an option to encrypt the files if the Add dialog is displayed. In some cases, however (e.g., when you choose Add to recently used Zip file), there is no Add dialog and therefore no opportunity to encrypt the files while they are being added. In these cases, you can encrypt files after they have been added, as described in the next section.

Encrypting files already in a Zip file

To encrypt files already in a Zip file:

when using the WinZip Ribbon interface, you can encrypt the all files in the Zip by opening the Tools tab, and clicking the Encrypt button. WinZip will display the Encrypt dialog asking for the password and will encrypt all files in the Zip. To encrypt just certain files in the Zip, select the files you wish to encrypt prior to clicking the Encrypt button. WinZip will ask for a password and then encrypt ONLY the selected files.

in Windows Explorer, right click on the Zip file and choose Encrypt from the WinZip shortcut menu. WinZip will ask for a password and then encrypt all files currently in the Zip file.

If a file in the Zip file is already encrypted, it will first be decrypted and then re-encrypted using the method and password you specified. WinZip will first try to decrypt the file using the current encryption password; if the file cannot be decrypted with this password, WinZip will ask you for the correct decryption password. If you are unable to supply the correct password, the file will be skipped, and it will remain unchanged in the Zip file.

Note that it is more efficient to encrypt files while they are being added to the Zip file than to encrypt them after they are already in the Zip file.

Notes on using encryption

The main WinZip window marks encrypted files with a lock icon in the Encrypted column. The Encrypted column indicates whether a file is encrypted or not and once the correct passphrase has been entered, indicates that the encrypted files are unlocked and accessible.
In the Encrypt and Decrypt dialogs, click the Show or Hide password indicator (Eye icon) to display, or prevent the password from being displayed, as you type it. Keeping the Verify password option checked will require you to type the password twice for confirmation (to avoid typographical errors).
The quality of the passwords you choose can greatly affect the security of your encrypted documents. Please read about passwords.
Be sure to keep track of your passwords! You will not be able to extract or open any files for which you do not have the correct password.