Brocade Communications Systems 12.4.00a Manual De Usuario

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ServerIron ADX Security Guide
135
53-1002440-03
Chapter
6
Secure Socket Layer (SSL) Acceleration
ServerIron ADX supports integrated hardware-based SSL acceleration. This chapter describes how 
to configure a ServerIron ADX for SSL acceleration in SSL Termination or SSL Proxy mode.
SSL support on the ServerIron ADX includes support for SSLv2, SSLv3, and TLS1.0.
SSL overview
The Secure Sockets Layer (SSL) protocol was developed by Netscape to provide security and 
privacy between client and server over the Internet. SSL supports server and client certificate 
verification, allowing protocols such as HTTP, FTP, and Telnet to be run on top of the verification 
process. SSL negotiates encryption keys and authenticates the server before data is exchanged by 
higher-level applications.
The SSL "handshake" is a key concept in this protocol. The handshake consists of two phases: 
server authentication, and an optional client certificate verification. In server authentication, the 
server sends its certificate and cipher preferences to a client that has made a request. The client 
then generates a master key, encrypts it with the public key of the server, and returns the 
encrypted master key to the server.
The server recovers the master key and authenticates itself to the client by returning a message 
encrypted with the master key. Subsequent data is encrypted and authenticated with keys derived 
from this master key. In the client certificate verification phase (which is optional), the server sends 
a challenge to the client, who authenticates itself to the server by returning a digital signature with 
its public-key certificate.
A variety of cryptographic algorithms are supported by SSL. During the "handshaking" process, the 
DSA public-key cryptosystem is used. After the exchange of keys, a number of ciphers are used that 
include RC4 and triple-DES for data encryption, and the SHA-1 and MD5 digest algorithm for 
message authentication.
Public Key Infrastructure (PKI)
In cryptography, a public key infrastructure (PKI) is an arrangement that provides for trusted third 
party vetting of, and vouching for, user identities. It also allows binding of public keys to users. This 
is usually carried out by software at a central location, together with other coordinated software at 
distributed locations. The public keys are typically in certificates.
The term PKI may mean both the certificate authority and related arrangements as well as, more 
broadly (which can sometimes be confusing), the use of public key algorithms in electronic 
communications. The latter meaning is erroneous since PKI methods are not required to use public 
key algorithms.