File Security

From an end user's perspective, file security is one of the most critical areas of security. Some file security is built into Linux: chmod (page 182) gives you basic security control. ACLs (Access Control Lists) allow for more fine-grained control of file access permissions. ACLs are part of Solaris, Windows NT/2000/XP, VAX/VMS, and mainframe operating systems. Red Hat Linux supports ACLs (page 185). Even these tools are insufficient, however, when your account is compromised (for example, by someone watching your fingers on the keyboard as you type your password). To provide maximum file security, you must encrypt your files. Then even someone who knows your password cannot read your files. (Of course, if someone knows your key, that person can decrypt your files if he or she can get to them.)