Link level security
Link level security refers to those security services that are invoked, directly or indirectly, by an MCA, the communications subsystem, or a combination of the two working together. This is illustrated in Figure 1.
Figure 1. Link level security and application level security
Here are some examples of link level security services:
- The MCA at each end of a message channel can authenticate its partner. This is done when the channel starts and a communications connection has been established, but before any messages start to flow. If authentication fails at either end, the channel is closed and no messages are transferred. This is an example of an identification and authentication service.
- A message can be encrypted at the sending end of a channel and decrypted at the receiving end. This is an example of a confidentiality service.
- A message can be checked at the receiving end of a channel to determine whether its contents have been deliberately modified while it was being transmitted over the network. This is an example of a data integrity service.
Parent topic:
Link level security and application level security