Encryption is applicable to all of the following OSI/ISO layers except:

A.
Network layer

B.
Physical layer

C.
Session layer

D.
Data link layer

Explanation:
The Physical Layer describes the physical properties of the various communications media, as well as
the electrical properties and interpretation of the exchanged signals. Ex: this layer defines the size of
Ethernet coaxial cable, the type of BNC connector used, and the termination method. You cannot

encrypt nothing at this layer because its physical, it is not protocol / software based. Network, Data
link and transport layer supports encryption.