Configuring SSL 1

Overview·· 1

SSL security services 1

SSL protocol stack· 1

FIPS compliance· 2

SSL configuration task list 2

Configuring an SSL server policy· 2

Configuring an SSL client policy· 4

Displaying and maintaining SSL 5

Overview

Secure Sockets Layer (SSL) is a cryptographic protocol that provides communication security for TCP-based application layer protocols such as HTTP. SSL has been widely used in applications such as e-business and online banking to provide secure data transmission over the Internet.

SSL security services

SSL provides the following security services:

·     Privacy—SSL uses a symmetric encryption algorithm to encrypt data and uses an asymmetric key algorithm such as RSA to encrypt the key used by the symmetric encryption algorithm. For more information about RSA, see "Managing public keys."

·     Authentication—SSL uses certificate-based digital signatures to authenticate the SSL server and client. The SSL server and client obtain digital certificates through PKI. For more information about PKI and digital certificates, see "Configuring PKI."

·     Integrity—SSL uses the message authentication code (MAC) to verify message integrity. It uses a MAC algorithm and a key to transform a message of any length to a fixed-length message. Any change to the original message will result in a change to the calculated fixed-length message. As shown in Figure 1, the message integrity verification process is as follows:

a.     The sender uses a MAC algorithm and a key to calculate a MAC value for a message. Then, it appends the MAC value to the message, and sends the message to the receiver.

b.     The receiver uses the same key and MAC algorithm to calculate a MAC value for the received message, and compares it with the MAC value appended to the message.

c.     If the two MAC values match, the receiver considers the message intact. Otherwise, the receiver considers that the message was tampered with and it discards the message.

Figure 1 MAC algorithm diagram

SSL protocol stack

The SSL protocol stack includes the following protocols:

·     SSL record protocol at the lower layer.

·     SSL handshake protocol, SSL change cipher spec protocol, and SSL alert protocol at the upper layer.

Figure 2 SSL protocol stack

The following describes the major functions of SSL protocols:

·     SSL record protocol—Fragments data received from the upper layer, computes and adds MAC to the data, and encrypts the data.

·     SSL handshake protocol—Negotiates the cipher suite used for secure communication, authenticates the server and client, and securely exchanges the keys between the server and client. The cipher suite that needs to be negotiated includes the symmetric encryption algorithm, key exchange algorithm, and MAC algorithm.

·     SSL change cipher spec protocol—Notifies the receiver that subsequent packets are to be protected based on the negotiated cipher suite and key.

·     SSL alert protocol—Sends alert messages to the receiving party. An alert message contains the alert severity level and a description.

FIPS compliance

The device supports the FIPS mode that complies with NIST FIPS 140-2 requirements. Support for features, commands, and parameters might differ in FIPS mode (see "Configuring FIPS") and non-FIPS mode.

SSL configuration task list

Configuring an SSL server policy

An SSL server policy is a set of SSL parameters used by the SSL server. An SSL server policy takes effect only after it is associated with an application such as HTTPS.

To configure an SSL server policy:

Configuring an SSL client policy

An SSL client policy is a set of SSL parameters that the client uses to establish a connection to the server. An SSL client policy takes effect only after it is associated with an application such as DDNS.

You can specify the SSL version (SSL 3.0 or TLS 1.0) for an SSL client policy:

·     If TLS 1.0 is specified and SSL 3.0 is not disabled, the client first uses TLS 1.0 to connect to the SSL server. If the connection attempt fails, the client uses SSL 3.0.

·     If TLS 1.0 is specified and SSL 3.0 is disabled, the client only uses TLS 1.0 to connect to the SSL server.

·     If SSL 3.0 is specified, the client uses SSL 3.0 to connect to the SSL server, whether you disable SSL 3.0 or not.

To enhance system security, H3C recommends disabling SSL 3.0 on the device and specifying TLS 1.0 for an SSL client policy.

To configure an SSL client policy:

Displaying and maintaining SSL

Execute display commands in any view.