Unencrypted Message
User
Encryption Performed
Message Delivery
Decryption Performed
User
Unencrypted Message
Figure 15 - Symmetric Cryptography
In Figure 15, the confidentiality provided to the message is done via a single key. Because the same key is used for encryption and decryption, this process is known as symmetric cryptography. Symmetric cryptography commonly has two attributes associated with it:
•It performs well – it is fast and easy to implement
•It has a key distribution problem – how do you get the symmetric key to everyone that needs it in a secure way?
Asymmetric cryptography is also available and functions very different than symmetric cryptography. It has two keys – one Public and one Private. The private key is not shared with anyone. The Public key is like a public telephone number. You can share it with everyone. Let’s look at Figure 16 – Asymmetric Cryptography.
13