Fonts

Most X terminals have some application fonts resident and download the others from other hosts. Again, any host masquerading as the TFTP host can download any font. Erroneous fonts can cause application errors, or crucial symbols could be replaced. For example, the ``exit without saving'' symbol could be replaced with a ``save and exit symbol.''

X provides the capability for implementing different access control mechanisms. Release 5 includes four mechanisms[Sch91]:

• Host Access Simple host-based access control.
• MIT-MAGIC-COOKIE-1 Shared plain-text ``cookies.''
• XDM-AUTHORIZATION-1 Secure DES based private-keys.
• SUN-DES-1 Based on Sun's Secure RPC system.