I did not know that the term Zip 2.0 encryption is synonymous with "password-protected Zip". Zip 2.0 encryption is the older encryption technique for Zip files that is known to be relatively weak. AES encryption however, is unbreakable. Chilkat Zip implements both: WinZip’s AES encryption and Zip 2.0 encryption. The Zip 2.0 encryption corresponds to the Zip component’s PasswordProtect property, whereas WinZip compatible AES encryption can be selected by setting the Zip component’s Encryption property = 4.
Chilkat Zip also offers custom encryption modes based on AES, Blowfish, or Twofish (in 128 to 256-bit encryption) when the Encryption property is set to 1, 2, or 3.