With the visual host key fingerprint, users can more easily tell whether they recognize a hex key using ssh. The secure shell remote connection program lets you connect to another machine via an encrypted connection.

Apparently, there is a setting in OpenSSH 5.1 and later for visual remote host fingerprinting. The basic concept is that it’s much easier for the human brain to notice a change in a visual pattern than in a string of hex digits. To turn it on, simply add a line that says
VisualHostKey yes to your ~/.ssh/config file. Then, when you go to SSH into a server, you’ll see a visual representation of the remote host fingerprint, in addition to the regular fingerprint, as shown below:

Example

[dhudson@attackbot ~]$ ssh myhost.com
Host key fingerprint is
07:d4:02:db:9f:70:d5:2d:7f:1b:6a:df:83:73:95:1d

+--[ RSA 2048]----+
|      ....  .. . |
|       +. ..  o .|
|      . +..    o |
|         = .   Eo|
|        S +   . B|
|         .   o oo|
|            . o o|
|             o +.|
|              o .|
+-----------------+