Red Hat CERTIFICATE 7.1 ADMINISTRATOR, Руководство администратора

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Certificates and Authentication
Appendix J Introduction to Public-Key Cryptography 777
Figure J-4 Using a Password to Authenticate a Client to a Server
These are the steps shown in Figure J-4:
1.
In response to an authentication request from the server, the client displays a dialog box
requesting the user’s name and password for that server. The user must supply a name
and password separately for each new server the user wishes to use during a work
session.
2.
The client sends the name and password across the network, either in the clear or over
an encrypted SSL connection.
3.
The server looks up the name and password in its local password database and, if they
match, accepts them as evidence authenticating the user’s identity.
4.
The server determines whether the identified user is permitted to access the requested
resource, and if so allows the client to access it.
With this arrangement, the user must supply a new password for each server, and the
administrator must keep track of the name and password for each user, typically on separate
servers.
As shown in the next section, one of the advantages of certificate-based authentication is
that it can be used to replace the first three steps in Figure J-4 with a mechanism that allows
the user to supply just one password (which is not sent across the network) and allows the
administrator to control user authentication centrally.