24-07-2012, 04:09 PM
Secured Shell
Secured Shell.ppt (Size: 2.99 MB / Downloads: 38)
What is SSH?
SSH – Secure Shell
SSH is a protocol for secure remote login and other secure network services over an insecure network
developed by SSH Communications Security Corp., Finland(1995 by Tatu)
Why SSH?
The traditional BSD 'r' - commmands (rsh, rlogin, rcp) are vulnerable to different kinds of attacks
The X Window System also has a number of severe vulnerabilities. With ssh, you can create secure remote X sessions which are transparent to the user.
Access control:
Suppose you want to permit another person to use your computer account, but only for certain purposes:
Port forwarding:
SSH can increase the security of other TCP/IP-based applications such as telnet, ftp, and the X Window System. A technique called port forwarding or tunneling reroutes a TCP/IP connection to pass through an SSH connection, transparently encrypting it end-to-end. Port forwarding can also pass such applications through network firewalls that otherwise prevent their use.
$ ssh -L 3002:localhost:119 news.yoyodyne.com
SSH security features
strong algorithms
uses well established strong algorithms for encryption, integrity, key exchange, and public key management
large key size
requires encryption to be used with at least 128 bit keys
supports larger keys too
algorithm negotiation
encryption, integrity, key exchange, and public key algorithms are negotiated
it is easy to switch to some other algorithm without modifying the base protocol