xStack DES-3500 Series Layer 2 Stackable Fast Ethernet Managed Switch User Manual
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Secure Socket Layer (SSL)
Secure Sockets Layer or SSL is a security feature that will provide a secure communication path between a host and client through
the use of authentication, digital signatures and encryption. These security functions are implemented through the use of a
ciphersuite
, which is a security string that determines the exact cryptographic parameters, specific encryption algorithms and key
sizes to be used for an authentication session and consists of three levels:
1.
Key Exchange:
The first part of the cyphersuite string specifies the public key algorithm to be used. This switch utilizes
the Rivest Shamir Adleman (RSA) public key algorithm and the Digital Signature Algorithm (DSA), specified here as the
DHE DSS
Diffie-Hellman (DHE) public key algorithm. This is the first authentication process between client and host as
they “exchange keys” in looking for a match and therefore authentication to be accepted to negotiate encryptions on the
following level.
2.
Encryption:
The second part of the ciphersuite that includes the encryption used for encrypting the messages sent
between client and host. The Switch supports two types of cryptology algorithms:
•
Stream Ciphers – There are two types of stream ciphers on the Switch,
RC4 with 40-bit keys
and
RC4 with 128-
bit keys
. These keys are used to encrypt messages and need to be consistent between client and host for optimal use.
•
CBC Block Ciphers – CBC refers to Cipher Block Chaining, which means that a portion of the previously
encrypted block of encrypted text is used in the encryption of the current block. The Switch supports the
3DES EDE
encryption code defined by the Data Encryption Standard (DES) to create the encrypted text.
3.
Hash Algorithm
: This part of the ciphersuite allows the user to choose a message digest function which will determine a
Message Authentication Code. This Message Authentication Code will be encrypted with a sent message to provide
integrity and prevent against replay attacks. The Switch supports two hash algorithms,
MD5
(Message Digest 5) and
SHA
(Secure Hash Algorithm).
These three parameters are uniquely assembled in four choices on the Switch to create a three-layered encryption code for secure
communication between the server and the host. The user may implement any one or combination of the ciphersuites available,
yet different ciphersuites will affect the security level and the performance of the secured connection. The information included in
the ciphersuites is not included with the Switch and requires downloading from a third source in a file form called a
certificate
.
This function of the Switch cannot be executed without the presence and implementation of the certificate file and can be
downloaded to the Switch by utilizing a TFTP server. The Switch supports SSLv3 and TLSv1. Other versions of SSL may not be
compatible with this Switch and may cause problems upon authentication and transfer of messages from client to host.
Download Certificate
Figure 7- 22. Download Certificate window
To download certificates, set the following parameters and click
Apply
.
Parameter
Description
Certificate Type
Enter the type of certificate to be downloaded. This type refers to the server responsible for
issuing certificates. This field has been limited to
local
for this firmware release.
Server IP
Enter the IP address of the TFTP server where the certificate files are located.
Certificate File Name
Enter the path and the filename of the certificate file to download. This file must have a .der
extension. (Ex. c:/cert.der)
Key File Name
Enter the path and the filename of the key file to download. This file must have a .der
extension (Ex. c:/pkey.der)
This window is used to download a certificate file for
the SSL function on the Switch from a TFTP server.
The certificate file is a data record used for
authenticating devices on the network. It contains
information on the owner, keys for authentication and
digital signatures. Both the server and the client must
have consistent certificate files for optimal use of the
SSL function. The Switch only supports certificate files
with .der file extensions. The Switch is shipped with a
certificate pre-loaded though the user may need to
download more, depending on user circumstances.
To view the following window, click
Configuration >
Secure Socket Layer (SSL) > Download Certificate
:
