The encryption method used on ZIP files depends on the software used to create the ZIP file. For example, WinZip and 7-Zip use AES (Advanced Encryption Standard) encryption, which is a symmetric encryption algorithm that is widely used and considered to be very secure. WinRAR uses a proprietary encryption algorithm, but also supports AES encryption. When creating a password-protected ZIP file, you can typically choose the encryption method and key strength, allowing you to customize the level of security for your files. It is important to choose a strong password and encryption method to ensure that your files are protected from unauthorized access.