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Self-Decrypting Archives

Another way to put files and folders into a single encrypted and compressed package. A Self-Decrypting Archives (SDAs) is slightly larger in size than a PGP Zip archive because the executable file is included in the archive, but this means that the SDA can be opened on Windows systems that don't have PGP Desktop installed. SDAs can only be protected by passphrases, so you have to find a secure way to communicate the passphrase of the SDA to the intended recipient.

If you have files, directories, or even entire drives on your system that you want to securely send to someone who doesn't have PGP Desktop installed, you can create a self-decrypting archive (SDA) of the data. An SDA is compressed, but the included executable makes it slightly larger than a PGP Zip archive would be with the same content. SDAs can only be opened on the same operating system as they were created on; so if you create an SDA on a Windows system, it can only be opened on another Windows system.

You can include directories in an SDA if you create it in Windows Explorer, as described below. To create an SDA of a file, folder, or drive in Windows Explorer:

  1. Open Windows Explorer.

  2. Select the files, folders, and/or drive you want to be in the SDA.

  3. Right-click the selected files, folders, and/or drive.

  4. Slide down to PGP Zip, then over to select Create SDA.

    The PGP Desktop - Enter Passphrase dialog appears.

    Screenshot of Passphrase dialog box

  5. Enter a passphrase that will be used to open the SDA you are creating. The Passphrase Quality bar provides a basic guideline for the strength of the passphrase you are creating by comparing the amount of entropy in the passphrase you enter against a true 128-bit random string (the same amount of entropy in an AES128 key). Filling the Passphrase Quality bar gives you a strong passphrase that could take in the billions (billions with a 'b') of years to brute-force decrypt.

    Normally, as an added level of security, the characters you enter for the passphrase are not visible on the screen. However, if you are sure that no one is watching (either physically or over the network) and you would like to see the characters of your passphrase as you type, check the Show Keystrokes checkbox.

  6. Click OK. You are prompted for a name and a location for the SDA you are creating.

    Screenshot of "save" dialog box

    The default location is the same location as the items in the SDA. The default filename is name.sda.exe, where "name" is the name of the first file or folder in the SDA.

  7. Select a location, specify a filename (or use the default), then click Save. The SDA is created at the specified location.