You must choose one of the three encryption algorithms that CZIP X offers to you.
General purpose algorithm created by Bruce Schneier characterized by decent encryption speed and a good level of protection against dictionary-based attacks. The weaknesses of this algorithm is still unknown, despite attempt to attack versions of BlowFish implemented with fewer rounds of encryption. Instead, CZIP X adopts the official implementation with 16 cycles of encryption and the only weakness could only derive from the use of a weak passphrase.
Bruce Schneier's algorithm that would represent the successor to BlowFish. Moderate encryption speed but good enough level of data protection, it is employed in the OpenPGP protocol. To date, it is believed that TwoFish is resistant to different types of attack, except for those based on brute force. Recommended for the protection of personal data.
Solid encryption algorithm that is also used by the U.S. Government. Moderate speed and high level of protection, it is believed that this algorithm is vulnerable to brute force attacks only with implementations that differ from the official scheme. Recommended for protection of sensitive documents and work.
If in doubt, Blowfish - for The ZipGenius Team - is the best choice and the one that offers the best balance between protection and speed, with Twofish being a good a but slower alternative; on the other side, if you are looking for the maximum protection, you should opt for Rijndael/AES.