Using Encryption

Please read about encryption.

Decrypting files

The correct password is required before WinZip® can extract an encrypted file from an archive. 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 extracts files not only for the Extract operation, but also when you view or open a file and when you use features such as Test, CheckOut, and Install.

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.

Encrypting files while adding

The most efficient way to encrypt files is to do so while you are adding them to an archive. To encrypt files while they are being added, simply check the Encrypt added files check box in the Add dialog. Before adding the files, WinZip will display the Encrypt dialog, where you will specify the password and encryption method.

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, either

open the Zip file and choose Encrypt from the Actions menu, or
right click the Zip file in My Computer or Windows Explorer and choose Encrypt from the WinZip shortcut menu.

In either case, WinZip will ask for a password and encryption method 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 an asterisk following the filename.
In the Encrypt and Decrypt dialogs, check the Mask password check box to prevent the password from being displayed as you type it. If you check this option, the Encrypt dialog 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.