If you need to give someone access to log into your account, you can do
so through Kerberos, without telling the person your password. Simply
create a file called .k5login in your home directory. This file
should contain the Kerberos principal (See What is a Kerberos Principal?.) of each person to whom you wish to give access. Each
principal must be on a separate line. Here is a sample .k5login
file:
jennifer@ATHENA.MIT.EDU
david@EXAMPLE.COM
This file would allow the users jennifer and
david to use your user ID, provided that they had
Kerberos tickets in their respective realms. If you will be logging
into other hosts across a network, you will want to include your own
Kerberos principal in your .k5login file on each of these hosts.
Using a .k5login file is much safer than giving out your
password, because:
You can take access away any time simply by removing the principal
from your .k5login file.
Although the user has full access to your account on one
particular host (or set of hosts if your .k5login file is shared,
e.g., over NFS), that user does not inherit your network privileges.
Kerberos keeps a log of who obtains tickets, so a system
administrator could find out, if necessary, who was capable of using
your user ID at a particular time.
One common application is to have a .k5login file in
root's home directory, giving root access to that machine to the
Kerberos principals listed. This allows system administrators to allow
users to become root locally, or to log in remotely as root,
without their having to give out the root password, and without anyone
having to type the root password over the network.