IP Security Protocol (IPSec)
Another widely used encryption protocol
- Can be used with other application layer protocols (not just for web applications)
Operations of IPSec between A and B
- A and B generate and exchange two random keys using Internet Key Exchange (IKE)
- Then combine these two numbers to create encryption key to be used between A and B
- Next, A and B negotiate the encryption technique to be used, such as DES or 3DES.
- A and B then begin transmitting data using either:
- Transport mode: only the IP payload is encrypted
- Tunnel mode: entire IP packet is encrypted (needs a new header for routing in Internet