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SSL configuration
SSL overview
Secure Sockets Layer (SSL) is a security protocol that provides secure connection services for TCP-based
application layer protocols, such as HTTP. It is widely used in E-business and online banking to ensure
secure data transmission over the Internet.
SSL security mechanism
Secure connections provided by SSL have these features:
Confidentiality—SSL uses a symmetric encryption algorithm to encrypt data and uses the asymmetric
key algorithm of Rivest, Shamir, and Adelman (RSA) to encrypt the key to be used by the symmetric
encryption algorithm.
Authentication—SSL supports certificate-based identity authentication of the server and client by
using the digital signatures. The SSL server and client obtain certificates from a certificate authority
(CA) through the Public Key Infrastructure (PKI).
Reliability—SSL uses the key-based message authentication code (MAC) to verify message integrity.
A MAC algorithm transforms a message of any length to a fixed-length message. With the key, the
sender uses the MAC algorithm to compute the MAC value of a message. Then, the sender suffixes
the MAC value to the message and sends the result to the receiver. The receiver uses the same key
and MAC algorithm to compute the MAC value of the received message, and compares the locally
computed MAC value with that received. If the two values match, the receiver considers the message
intact; otherwise, the receiver considers that the message has been tampered with in transit and
discards the message.
Figure 72
Message integrity verification by a MAC algorithm
Key
Message
Sender
Message
Send to
the
receiver
MAC
Key
Receiver
Compare
Message
Compute
the MAC
Compute
the MAC
MAC
MAC
NOTE:
For more information about symmetric key algorithms, asymmetric key algorithm RSA and digital signature, see
the chapter “Public key configuration.“
For more information about PKI, certificate, and CA, see the chapter “PKI configuration.“
