Asymmetric algorithms
Asymmetric algorithms use a PKI environment as they use two keys: a private key that is always kept and a Public key that is always given away. Let us now look at different asymmetric techniques:
- Diffie Hellman: Diffie Hellman does not encrypt data; its main purpose is to create a secure session so that symmetric data can travel down it. The Diffie Hellman handshake is shown in the following diagram:
Figure 9: Diffie Hellman
Diffie Hellman creates the keys used in the Internet Key Exchange (IKE); it uses UDP Port 500 to set up the secure session for the L2TP/IPSec VPN. Once the secure tunnel has been created, then the symmetric encrypted data flows down the tunnel.
- Rivest, Shamir, and Adelman (RSA): RSA is named after the three people who invented the algorithm. The keys were the first private and public key pairs, and they start are 1,024, 2046, 3,072 and 4,096 bits. They are used for encryption and digital signatures.
- Digital Signature Algorithm (DSA): DSA keys are used...
