Disk Copy (/Applications/Utilities/), or Disk Utility (/Applications/Utilities/) for Mac OS X 10.3 Panther, offers the option of using encrypted disk images. To learn how to create one, see technical document 107333, "
Mac OS X: How to Create Encrypted Disk Images".
An encrypted disk image can be used like any other disk image file. It may be copied to or created on network volumes or removable media, including Zip drives, USB flash media, or FireWire hard drives. You should not create images directly onto CD-Rs or DVD-Rs, but encrypted disk images can be burned onto a CD-R or DVD-R for archival purposes.
Each encrypted disk image is protected by a password, which may be composed of 7-bit ASCII characters and 1 to 255 characters in length. For more information, see technical document 106521, "
Mac OS X: How to Choose a Secure Password".
Warning: The encryption used is 128-bit, equivalent to that used in the banking industry. If you forget the password to your encrypted disk image, your data will be irretrievably lost. By default, the password is stored in your login keychain when you create an encrypted disk image. The keychain uses the same password that you use to log in to the system. You should use the keychain to store this password.
Notes
1. Backup programs will need to back up the entire image if any file stored within the image has changed, since the image appears as a single file.
2. There is no way to change the password on an image file.
3. An encrypted disk image cannot be used as your home directory.