CEH

Applications of Cryptography 73

1. Click Start ➢ All Programs ➢ Administrative Tools ➢ Local Security Policy.


2. Select the Local Computer node ➢ IP Security Policies, and in the right pane right-click
   the Secure21 policy and click Assign.
   On Computer B:


3. In the Local Security Policy Microsoft Management Console (MMC) console, on the
   Local Computer node right-click IP Security Policies, select All Tasks, and then click
   Export Policies.


4. In the Save As dialog box, type C:\IPSecPolicy\IPsecurityPolicy21.ipsec , and then click
   Save. You must then save the IPSec policy.
   Import the security policy to a Windows machine.
   Next, configure a Security Association rule in the Windows Firewall with Advanced
   Security MMC:


5. On Computer A, click Start ➢ Administrative Tools ➢ Windows Firewall With
   Advanced Security.


6. Select and then right-click Connection Security Rules, and then click New Rule.


7. In the New Connection Security Rule Wizard, select Server-To-Server, and then click
   Next.


8. On the Endpoints screen, select Any IP Address for both options, and then click Next.


9. On the Requirements screen, select Require Authentication For Inbound And Out-
   bound Connections, and then click Next.


10. On the Authentication Method screen, select Preshared Key, type password in the text
    box, and then click Next.


11. On the Profile screen, verify that the Domain, Private, and Public options are selected,
    and then click Next.


12. In the Name text box, type Secure Server Authentication Rule , and then click Finish.


13. Perform steps 1–8 on Computer B.

Pretty Good Privacy

Pretty Good Privacy (PGP) is another application of cryptographic technologies. Using pub-
lic key encryption, PGP is one of the most widely recognized cryptosystems in the world.
PGP has been used to protect the privacy of e-mail, data, data storage, and other forms of
communication such as instant messaging.

Early versions of PGP were written by its creator Philip Zimmermann and

first offered to the public in 1991. The program is one example of an open

source application and as such has several different versions available,

with everyone having an opinion about which is best.