Someone who cannot decrypt the contents of an archive may still be able to infer sensitive information just from the unencrypted names of files and folders. To prevent this, you can encrypt the names of files (and folders) in addition to their contents. Encrypted file names can be viewed only by an intended recipient or by someone who has a passphrase used to encrypt. Anyone else sees no file names at all.
To automatically encrypt file names when encrypting files: Check the Encrypt file names box on the Zip Security Options page.
Encrypting File Names When You Update an Archive
If you add files to an archive that already contains files with unencrypted file names, Smartcrypt encrypts the names of all files in the archive.
If the archive contains files whose contents are already encrypted, Smartcrypt decrypts these files and then re-encrypts them, and their names, using the encryption method (passphrase/recipient list) and algorithm currently set in Security options.
If Smartcrypt cannot decrypt some files, Smartcrypt leaves them with their original encryption but applies new encryption to the other files and to all file names.
If you add files to an archive that already contains files with encrypted file names, Smartcrypt encrypts the newly added files and their names using the same passphrase, Smartkey or recipient list originally used to encrypt file names in the archive.