Ssh2.0 Overview - 3Com Switch 4800G 24-Port Configuration Manual

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SSH2.0 Overview

Algorithm and Key
Asymmetric Key
Algorithm
SSH C
When configuring SSH, go to these sections for information you are interested in:
"SSH2.0 Overview" on page 1107
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"Configuring the Device as an SSH Server" on page 1110
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"Configuring the Device as an SSH Client" on page 1115
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"Displaying and Maintaining SSH" on page 1118
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"SSH Server Configuration Examples" on page 1119
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"SSH Client Configuration Examples" on page 1125
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Secure Shell (SSH) offers an approach to securely logging into a remote device. By
encryption and strong authentication, it protects devices against attacks such as IP
spoofing and plain text password interception.
The device can not only work as an SSH server to support connections with SSH
clients, but also work as an SSH client to allow users to establish SSH connections
with a remote device acting as the SSH server.
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Currently, when acting as an SSH server, the device supports two SSH versions:
SSH2 and SSH1. When acting as an SSH client, the device supports SSH2 only.
Algorithm is a set of transformation rules for encryption and decryption.
Information without being encrypted is known as plain text, while information
that is encrypted is known as cipher text. Encryption and decryption are performed
using a string of characters called a key, which controls the transformation
between plain text and cipher text, for example, changing the plain text into
cipher text or cipher text into plain text.
Figure 330 Encryption and decryption
Plain text
Encryption
Key-based algorithm is usually classified into symmetric key algorithm and
asymmetric key algorithm.
Asymmetric key algorithm means that a key pair exists at both ends. The key pair
consists of a private key and a public key. The public key is effective for both ends,
while the private key is effective only for the local end.
ONFIGURATION
Key
Cipher text
Decryption
Key
Plain text