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SSL protocol stack
The SSL protocol consists of two layers of protocols: the SSL record protocol at the lower layer and the SSL
handshake protocol, change cipher spec protocol, and alert protocol at the upper layer.
Figure 73
SSL protocol stack
Application layer protocol (e.g. HTTP)
TCP
IP
SSL handshake protocol
SSL change cipher spec protocol
SSL alert protocol
SSL record protocol
SSL record protocol—Fragments data to be transmitted, computes and adds MAC to the data, and
encrypts the data before transmitting it to the peer end.
SSL handshake protocol—A very important part of the SSL protocol stack, responsible for
negotiating the cipher suite to be used for secure communication (including the symmetric encryption
algorithm, key exchange algorithm, and MAC algorithm), securely exchanging the key between the
server and client, and implementing identity authentication of the server and client. Through the SSL
handshake protocol, a session is established between a client and the server. A session consists of a
set of parameters, including the session ID, peer certificate, cipher suite, and master secret.
SSL change cipher spec protocol—Used for notification between the client and the server that the
subsequent packets are to be protected and transmitted based on the newly negotiated cipher suite
and key.
SSL alert protocol—Enables the SSL client and server to send alert messages to each other. An alert
message contains the alert severity level and a description.
SSL configuration task list
Complete the following tasks to configure SSL:
Task
Remarks
Configuring an SSL server policy
Required
Configuring an SSL client policy
Optional
Configuring an SSL server policy
An SSL server policy is a set of SSL parameters for a server to use when booting up. An SSL server policy
takes effect only after it is associated with an application layer protocol such as HTTP.
Configuration prerequisites
Configure the PKI domain for the SSL server policy to use to obtain the server side certificate. For more
information about PKI domain configuration, see the chapter ―PKI configuration.―