ARCHIVED: In Mac OS 9, what is Apple File Security, and how do I use it to encrypt a file?

Introduced in Mac OS 9, Apple File Security is a utility for encrypting files so that they cannot be opened without entering a password. It initially used 56-bit key encryption, but to improve security, Apple upgraded it in OS 9.1 to use a 128-bit key instead. To use it, follow these steps:

1. In the Finder, highlight the file you would like to encrypt by clicking it once.
   
   
2. From the File menu, choose Encrypt. Apple File Security will prompt you to enter a password and confirmation. By default, the file's password will be added to any Mac OS Keychain, unless you clear the Add to Keychain checkbox.

Note: If you add a file's password to the Keychain, you only have to remember the Keychain's password in order to access the file. On the other hand, you will need to remember every password not added to the Keychain. In this case, you should be careful to remember passwords assigned to individual files.

The following items can't be encrypted:

• Folders
  
  
• Disks
  
  
• Volumes
  
  
• Items in the System Folder
  
  
• Items that are open or locked

Also see:

• What are the major differences between versions of the Macintosh operating system?