Supported Zip file encryption
SQLBackupAndFTP allows you to encrypt your backup files using 2 encryption methods (offered only for the Professional version):
1. ZIP compatible
It supports a simple password-based symmetric encryption. Note that it provides basic encryption only and is vulnerable to known-plaintext attacks. You can use built-in Windows compressor to open backups encrypted using ZIP compatible encryption method.
2. WinZip AES
AES is a strong encryption standard adopted by the U.S. government. Built-in Windows compressor does not support AES files, so you have to use 7Zip (freeware) or WinZip 9.0 (or higher) to open backups encrypted using WinZip AES encryption method.
Also, note that backup files over 2 GB are zipped using Zip64 format.
Built-in Windows compressor does not support Zip64, so use 7Zip (freeware) or another archiver to uncompress it.
You can download SQLBackupAndFTP and try this feature from here.