The Firebox cannot scan the contents of encrypted zip files even if HTTPS content inspection is enabled.
HTTPS content inspection allows the Firebox to inspect encrypted HTTPS traffic by decrypting it. However, the content within encrypted zip files remains inaccessible to Gateway AntiVirus scanning because the encryption key for the zip file is not available to the Firebox. This limitation is consistent with standard network security practices, where encrypted files need to be decrypted with a known key before content scanning can occur.